subject_51449.htm

vc

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序号：51449 发表者：天才 发表日期：2003-09-01 17:07:36
<br>主题：关于赋值运算符的重载
<br>内容：请看下面有两种重载赋值运算符的方法：<BR>class student<BR>{<BR>private:<BR>&nbsp;&nbsp;&nbsp;&nbsp;student() {}<BR>public:<BR>&nbsp;&nbsp;&nbsp;&nbsp;student(unsigned int iID,unsigned int iAge):m_iID(iID),m_iAge(iAge) {}<BR>&nbsp;&nbsp;&nbsp;&nbsp;/*void operator=(const student&amp; s)<BR>&nbsp;&nbsp;&nbsp;&nbsp;{<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if(&amp;s!=this)<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;m_iID=s.m_iID;<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;m_iAge=s.m_iAge;<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<BR>&nbsp;&nbsp;&nbsp;&nbsp;}*/<BR>&nbsp;&nbsp;&nbsp;&nbsp;student&amp; operator=(const student&amp; s)<BR>&nbsp;&nbsp;&nbsp;&nbsp;{<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if(&amp;s!=this)<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;m_iID=s.m_iID;<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;m_iAge=s.m_iAge;<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return *this;<BR>&nbsp;&nbsp;&nbsp;&nbsp;}<BR>&nbsp;&nbsp;&nbsp;&nbsp;void print()<BR>&nbsp;&nbsp;&nbsp;&nbsp;{<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;std::cout&lt;&lt;&#34;ID is &#34;&lt;&lt;m_iID&lt;&lt;&#34; and Age is &#34;&lt;&lt;m_iAge&lt;&lt;std::endl;<BR>&nbsp;&nbsp;&nbsp;&nbsp;}<BR>private:<BR>&nbsp;&nbsp;&nbsp;&nbsp;unsigned int m_iID;<BR>&nbsp;&nbsp;&nbsp;&nbsp;unsigned int m_iAge;<BR>};<BR><BR>问：<BR>这两种方法有什么区别？还是除了写法没有区别？
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回复者：dongfanghong 回复日期：2003-09-01 17:22:13
<br>内容：有区别：<BR>第二种支持：<BR>a=b=c<BR>这种写法
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<font color=red>答案被接受</font><br>回复者：iamhere 回复日期：2003-09-01 17:24:15
<br>内容：区别在于返回值的不同，返回值为student&amp;的还可以这么调用：<BR>student s1( 100 , 20 );<BR>student s2( 200 , 10 ); ;<BR>student s3 = ( s2 = s1 );<BR>而返回值为void *的却是不能
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回复者：天才 回复日期：2003-09-02 09:08:50
<br>内容：因为iamhere使用了s3=(s2=s1)这种表达方式，而且叙述较详细，所以分给您了，东方兄不好意思了。
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回复者：dongfanghong 回复日期：2003-09-02 13:00:53
<br>内容：吸取教训，高手和菜鸟的差别啊，就是是否写清楚了。<BR>2003-9-2 13:03:42