class="htmledit_views">

http://blog.csdn.net/whyglinux/archive/2006/02/18/602329.aspx

 

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">类的成员函数后面加 const，表明这个函数不会对这个类对象的数据成员（准确地说是非静态数据成员）作任何改变。

 

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">在设计类的时候，一个原则就是对于不改变数据成员的成员函数都要在后面加 const，而对于改变数据成员的成员函数不能加 const。所以 const 关键字对成员函数的行为作了更加明确的限定：有 const 修饰的成员函数（指 const 放在函数参数表的后面，而不是在函数前面或者参数表内），只能读取数据成员，不能改变数据成员；没有 const 修饰的成员函数，对数据成员则是可读可写的。

 

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">除此之外，在类的成员函数后面加 const 还有什么好处呢？那就是常量（即 const）对象可以调用 const 成员函数，而不能调用非const修饰的函数。正如const类型的数据可以给非const类型的变量赋值一样，反之则不成立。

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class</a>="cpp">#include <iostream> #include <<a <a class="tags" href="/tags/CLASS.html" title=class>class</a>="tags" href="/tags/STRING.html" title=string>string</a>> using namespace std; <a class="tags" href="/tags/CLASS.html" title=class>class</a> Student { public: Student() {} Student( const <a <a class="tags" href="/tags/CLASS.html" title=class>class</a>="tags" href="/tags/STRING.html" title=string>string</a>& nm, int sc = 0 ) : name( nm ), score( sc ) {} void set_student( const <a <a class="tags" href="/tags/CLASS.html" title=class>class</a>="tags" href="/tags/STRING.html" title=string>string</a>& nm, int sc = 0 ) { name = nm; score = sc; } const <a <a class="tags" href="/tags/CLASS.html" title=class>class</a>="tags" href="/tags/STRING.html" title=string>string</a>& get_name() const { return name; } int get_score() const { return score; } private: <a <a class="tags" href="/tags/CLASS.html" title=class>class</a>="tags" href="/tags/STRING.html" title=string>string</a> name; int score; }; // <a <a class="tags" href="/tags/CLASS.html" title=class>class</a>="tags" href="/tags/OUTPUT.html" title=output>output</a> student's name and score void <a <a class="tags" href="/tags/CLASS.html" title=class>class</a>="tags" href="/tags/OUTPUT.html" title=output>output</a>_student( const Student& student ) { cout << student.get_name() << "/t"; cout << student.get_score() << endl; } int main() { Student stu( "Wang", 85 ); <a <a class="tags" href="/tags/CLASS.html" title=class>class</a>="tags" href="/tags/OUTPUT.html" title=output>output</a>_student( stu ); }

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">设 计了一个类 Student，数据成员有 name 和 score，有两个构造函数，有一个设置成员数据函数 set_student()，各有一个取得 name 和 score 的函数 get_name() 和 get_score()。请注意 get_name() 和 get_score() 后面都加了 const，而 set_student() 后面没有（也不能有const）。

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">首先说一点题外话，为什么 get_name() 前面也加 const。如果没有前后两个 const 的话，get_name() 返回的是对私有数据成员 name 的引用，所以通过这个引用可以改变私有成员 name 的值，如

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">Student stu( "Wang", 85 );
stu.get_name() = "Li";

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">即把 name 由原来的 "Wang" 变成了 "Li"，而这不是我们希望的发生的。所以在 get_name() 前面加 const 避免这种情况的发生。

那么，get_name() 和 get_score() 这两个后面应该加 const的成员函数，如果没有 const 修饰的话可不可以呢？回答是可以！但是这样做的代价是：const对象将不能再调用这两个非const成员函数了。如

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class</a>="cpp">const <a <a class="tags" href="/tags/CLASS.html" title=class>class</a>="tags" href="/tags/STRING.html" title=string>string</a>& get_name(); // 这两个函数都应该设成 const 型 int get_score(); void <a <a class="tags" href="/tags/CLASS.html" title=class>class</a>="tags" href="/tags/OUTPUT.html" title=output>output</a>_student( const Student& student ) { cout << student.get_name() << "/t"; // 如果 get_name() 和 get_score() 是非const成员函数，这一句和下一句调用是错误的 cout << student.get_score() << endl; }

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">由 于参数student表示的是一个对const Student型对象的引用，所以 student 不能调用非const成员函数如 set_student()。如果 get_name() 和 get_score() 成员函数也变成非const型，那么上面的 student.get_name() 和 student.get_score() 的使用就是非法的，这样就会给我们处理问题造成困难。

因此，我们没有理由反对使用const，该加const时就应该加上const，这样使成员函数除了非const的对象之外，const对象也能够调用它。

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">/

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class</a>="cpp"><a class="tags" href="/tags/CLASS.html" title=class>class</a> Pig { long _lx; public: Pig(const long& _x = 9) : _lx(_lx){} void show(void) { cout<<"Pig的成员_lx:"<<_lx<<endl; } };

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="tags" href="/tags/BianYiQi.html" title=编译器>编译器会对上述声明中的show()函数加入一个隐晦的this指针，其声明类似如下:class="Apple-converted-space"> 
class</a>="cpp">void show(Pig* const this) { ...... }

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">这样当类被实例化为对象变量后，show凭借上述this指针就可以参阅到其数据成员_lx!class="Apple-converted-space"> 

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">但是当类被实例化为常型对象后，类的数据成员就具有了常量属性，这样的this指针就不能再参阅其类成员_lx了，因为语言规则不允许以非常型指针去访问常量!

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">例如:class="Apple-converted-space"> 

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class</a>="cpp"><a class="tags" href="/tags/CLASS.html" title=class>class</a> Pig { long _lx; public: Pig(const long& _x = 9):_lx(_x){} void show(void)//未加const修饰!!! { cout <<"Pig的成员_lx:"<<_lx<<endl; } }; int main() { const Pig _p; /*如下 "_p.show(); "语句将生成: errorC2662:Pig::show ":不能将 "this "指针从 "const Pig "转换为 "Pig & " */ _p.show();//!不能通过编译! _PAUSE; return 0; }

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">为解决上述问题，可把show()成员函数声明为常型成员函数，这样class="tags" href="/tags/BianYiQi.html" title=编译器>编译器将为show()函数插入新的this指针，类似声明如下：class="Apple-converted-space"> 

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">void   show(const   Pig*   const   this)   const//!!!class="Apple-converted-space"> 
{class="Apple-converted-space"> 
        ......class="Apple-converted-space"> 
}class="Apple-converted-space"> 

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">这个新的this指针将可以访问包括常量在内的数据类成员!class="Apple-converted-space"> 

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">例如:

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class</a>="cpp"><a class="tags" href="/tags/CLASS.html" title=class>class</a> Pig { long _lx; public: Pig(const long& _x = 9) : _lx(_x){} void show(void)const//声明为常型成员函数! { cout < < "Pig的成员_lx: " < < _lx < < endl; } }; int main() { const Pig _p;//声明为常型对象! _p.show();//行为良好！输出 "Pig的成员_lx: 9 " ! _PAUSE; return 0; }

class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 21px; font-family: verdana, sans-serif; font-size: 13px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">class="Apple-converted-space">class="Apple-style-span" style="widows: 2; text-transform: none; text-indent: 0px; border-collapse: separate; font: medium 宋体; white-space: normal; orphans: 2; letter-spacing: normal; color: #000000; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;">class="Apple-style-span" style="text-align: left; line-height: 23px; font-family: simsun; font-size: 14px;">以上就是成员函数后面加const的原因!