class="tags" href="/tags/CLASS.html" title=class>class="Apple-style-span" style="TEXT-ALIGN: center; 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="tags" href="/tags/CLASS.html" title=class>class="Apple-style-span" style="TEXT-ALIGN: left; LINE-HEIGHT: 22px; FONT-FAMILY: Arial, Helvetica, sans-serif; COLOR: #2e3c78; FONT-SIZE: 14px">

转自:http://linpder.blog.163.com/blog/static/487641020095231925257/

运算符在重载的时候有两种方式࿰c;一是成员函数方式࿰c;二是成友元（friend）函数方式。class="tags" href="/tags/CLASS.html" title=class>class="Apple-converted-space"> 
成员函数比较简单。下面是一个示例代码：class="tags" href="/tags/CLASS.html" title=class>class="Apple-converted-space"> 
c</a>ode" <a <a class="tags" href="/tags/C.html" title=c>c</a>lass="tags" href="/tags/CLASS.html" title=<a class="tags" href="/tags/C.html" title=c>c</a>lass><a class="tags" href="/tags/C.html" title=c>c</a>lass</a>="<a class="tags" href="/tags/C.html" title=c>c</a>pp"><a <a class="tags" href="/tags/C.html" title=c>c</a>lass="tags" href="/tags/CLASS.html" title=<a class="tags" href="/tags/C.html" title=c>c</a>lass><a class="tags" href="/tags/C.html" title=c>c</a>lass</a> Complex { private: double real; double img; publi<a class="tags" href="/tags/C.html" title=c>c</a>: Complex(){} Complex(double i,double j):real(i),img(j) { } Complex operator+(<a class="tags" href="/tags/C.html" title=c>c</a>onst Complex &<a class="tags" href="/tags/C.html" title=c>c</a>x) { return Complex(real+<a class="tags" href="/tags/C.html" title=c>c</a>x.real,img+<a class="tags" href="/tags/C.html" title=c>c</a>x.img); } };

如果是设置成友元函数࿰c;一定要注意：class="tags" href="/tags/CLASS.html" title=class>class="Apple-converted-space"> 
color: #0000ff;">（1）当重载友元函数时࿰c;将没有隐含的参数this指针。这样࿰c;对双目运算符࿰c;友元函数有2个参数࿰c;对单目运算符࿰c;友元函数有一个参数。class="tags" href="/tags/CLASS.html" title=class>class="Apple-converted-space"> 
（2）有些运行符不能重载为友元函数࿰c;它们是：color: #ff8040;">=,(),[]和-＞。class="tags" href="/tags/CLASS.html" title=class>class="Apple-converted-space"> 
因此࿰c;上面那个+运算符如果是重载为友元函数的话࿰c;应该写成：class="tags" href="/tags/CLASS.html" title=class>class="Apple-converted-space"> 
c</a>ode" <a <a class="tags" href="/tags/C.html" title=c>c</a>lass="tags" href="/tags/CLASS.html" title=<a class="tags" href="/tags/C.html" title=c>c</a>lass><a class="tags" href="/tags/C.html" title=c>c</a>lass</a>="<a class="tags" href="/tags/C.html" title=c>c</a>pp"><a <a class="tags" href="/tags/C.html" title=c>c</a>lass="tags" href="/tags/CLASS.html" title=<a class="tags" href="/tags/C.html" title=c>c</a>lass><a class="tags" href="/tags/C.html" title=c>c</a>lass</a> Complex { private: double real; double img; publi<a class="tags" href="/tags/C.html" title=c>c</a>: Complex(){} Complex(double i,double j):real(i),img(j) { } // 注意： 有两个参数 friend Complex operator+(<a class="tags" href="/tags/C.html" title=c>c</a>onst Complex &<a class="tags" href="/tags/C.html" title=c>c</a>x1,<a class="tags" href="/tags/C.html" title=c>c</a>onst Complex &<a class="tags" href="/tags/C.html" title=c>c</a>x2) { return Complex(<a class="tags" href="/tags/C.html" title=c>c</a>x1.real+<a class="tags" href="/tags/C.html" title=c>c</a>x2.real,<a class="tags" href="/tags/C.html" title=c>c</a>x1.img+<a class="tags" href="/tags/C.html" title=c>c</a>x2.img); } void Out() { <a class="tags" href="/tags/C.html" title=c>c</a>out << real << "+" << img << "i" << endl; } };

还需要注意一点࿰c;有的VC 6.0class="tags" href="/tags/BianYiQi.html" title=编译器>编译器在编译上面代码的时候会报错࿰c;错误为：class="tags" href="/tags/CLASS.html" title=class>class="Apple-converted-space"> 
color: #ff0000;">fatal error C1001: INTERNAL COMPILER ERRORclass="tags" href="/tags/CLASS.html" title=class>class="Apple-converted-space"> 
原因是VCclass="tags" href="/tags/BianYiQi.html" title=编译器>编译器本身的问题。class="tags" href="/tags/CLASS.html" title=class>class="Apple-converted-space"> 
解决办法：class="tags" href="/tags/CLASS.html" title=class>class="Apple-converted-space"> 在类的声明之前再加上一个声明。具体代码如下：class="tags" href="/tags/CLASS.html" title=class>class="Apple-converted-space"> 

c</a>ode" <a <a class="tags" href="/tags/C.html" title=c>c</a>lass="tags" href="/tags/CLASS.html" title=<a class="tags" href="/tags/C.html" title=c>c</a>lass><a class="tags" href="/tags/C.html" title=c>c</a>lass</a>="<a class="tags" href="/tags/C.html" title=c>c</a>pp"><a <a class="tags" href="/tags/C.html" title=c>c</a>lass="tags" href="/tags/CLASS.html" title=<a class="tags" href="/tags/C.html" title=c>c</a>lass><a class="tags" href="/tags/C.html" title=c>c</a>lass</a> Complex; Complex operator+(<a class="tags" href="/tags/C.html" title=c>c</a>onst Complex &<a class="tags" href="/tags/C.html" title=c>c</a>x1,<a class="tags" href="/tags/C.html" title=c>c</a>onst Complex &<a class="tags" href="/tags/C.html" title=c>c</a>x2); <a <a class="tags" href="/tags/C.html" title=c>c</a>lass="tags" href="/tags/CLASS.html" title=<a class="tags" href="/tags/C.html" title=c>c</a>lass><a class="tags" href="/tags/C.html" title=c>c</a>lass</a> Complex { private: double real; double img; publi<a class="tags" href="/tags/C.html" title=c>c</a>: Complex(){} Complex(double i,double j):real(i),img(j) { } // 注意：有两个参数 friend Complex operator+(<a class="tags" href="/tags/C.html" title=c>c</a>onst Complex &<a class="tags" href="/tags/C.html" title=c>c</a>x1,<a class="tags" href="/tags/C.html" title=c>c</a>onst Complex &<a class="tags" href="/tags/C.html" title=c>c</a>x2) { return Complex(<a class="tags" href="/tags/C.html" title=c>c</a>x1.real+<a class="tags" href="/tags/C.html" title=c>c</a>x2.real,<a class="tags" href="/tags/C.html" title=c>c</a>x1.img+<a class="tags" href="/tags/C.html" title=c>c</a>x2.img); } void Out() { <a class="tags" href="/tags/C.html" title=c>c</a>out << real << "+" << img << "i" << endl; } };

这样就没有问题了。