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<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"></font><font FACE="??ì?,SimSun" LANG="ZH-CN" size="2">派生类构造函数的调用顺序如下：</font></p>
<font SIZE="3">
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"></font><font size="2"><font FACE="??ì?,SimSun" LANG="ZH-CN">①</font>
<font FACE="??ì?,SimSun" LANG="ZH-CN">基类的构造函数</font></font></p>
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<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"></font><font size="2"><font FACE="??ì?,SimSun" LANG="ZH-CN">②</font>
<font FACE="??ì?,SimSun" LANG="ZH-CN">子对象类的构造函数（如果有的话）</font></font></p>
<font SIZE="3">
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"></font><font size="2"><font FACE="??ì?,SimSun" LANG="ZH-CN">③</font>
<font FACE="??ì?,SimSun" LANG="ZH-CN">派生类构造函数</font></font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"> </p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2"><font FACE="??ì?,SimSun" LANG="ZH-CN"><a href="example4-2.htm" target="_blank">【例</a></font><a href="example4-2.htm" target="_blank">4-2<font FACE="??ì?,SimSun" LANG="ZH-CN">】</font></a><font FACE="??ì?,SimSun" LANG="ZH-CN">派生类构造函数举例。</font></font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2"><font FACE="??ì?,SimSun" LANG="ZH-CN"><a href="example4-3.htm" target="_blank">【例</a></font><a href="example4-3.htm" target="_blank">4-3<font FACE="??ì?,SimSun" LANG="ZH-CN">】</font></a><font FACE="??ì?,SimSun" LANG="ZH-CN">看程序的执行结果。</font></font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"> </p>
<p ALIGN="justify" style="line-height: 200%; margin-top: 0; margin-bottom: 0"><font FACE="oúì?,SimHei" LANG="ZH-CN" size="2">(3)
析构函数</font></p>
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<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"></font><font FACE="??ì?,SimSun" LANG="ZH-CN" size="2">当对象被删除时，派生类的析构函数被执行。由于析构函数也不能被继承，因此在执行派生类的析构函数时，基类的析构函数也将被调用。执行顺序是先执行派生类的析构函数，再执行基类的析构函数，其执行顺序与执行构造函数正好相反。</font></p>
<p ALIGN="justify" style="line-height: 200%; margin-top: 0; margin-bottom: 0"><font FACE="oúì?,SimHei" LANG="ZH-CN" size="2">(4)
组合</font></p>
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<p style="line-height: 100%; margin-top: 0; margin-bottom: 0"></font><font FACE="??ì?,SimSun" LANG="ZH-CN" size="2">若类以另一个类的对象作为数据成员，称为组合。</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font FACE="??ì?,SimSun" LANG="ZH-CN" size="2">例如：</font></p>
<blockquote>
<blockquote>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">#class
Vehicle</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">{</font></p>
<blockquote>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">//...</font></p>
</blockquote>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">}</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">class
Motor</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">{</font></p>
<blockquote>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">//...</font></p>
</blockquote>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">}</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">class
Car:public Vehicle</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">{</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">public:</font></p>
<blockquote>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">Motor
motor; <font color="#FF6600">//<font FACE="??ì?,SimSun" LANG="ZH-CN">包含一个对象数据成员</font></font></font></p>
</blockquote>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">};</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">void
vehicleFn(Vehicle& v);</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">void
motorFn(Motor& m);</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"> </p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">void
main( )</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">{</font></p>
<blockquote>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">car
c;</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">vechileFn(c);</font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">motorFn(c);
<font color="#FF0000">//<font FACE="??ì?,SimSun" LANG="ZH-CN">错误</font></font></font></p>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">motorFn(c.motor);</font></p>
</blockquote>
<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"><font size="2">}</font></p>
</blockquote>
</blockquote>
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<p ALIGN="JUSTIFY" style="line-height: 100%; margin-top: 0; margin-bottom: 0"></font><font FACE="??ì?,SimSun" LANG="ZH-CN" size="2">在设计较复杂的程序中，这种现象比较常见。</font></p>
<p style="line-height: 100%; text-indent: 0; margin: 0" class="右标题" align="left"> </p>
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