学步园

http://stackoverflow.com/questions/1501920/base-copy-constructor-not-called#ifndef CSHAPE_H<br /> #define CSHAPE_H<br /> #include <string><br /> using namespace std;</p> <p>//有关C++的构造以及析构的经典总结(constructor,copy constructor,operator=,destructor)：<br /> /*<br /> 1）首先对于nontrivial的类(即有virtual method,vtable等),不管你写(自定义)或是没写(default)<br /> copy control,constructor,destructor,编译器都会为你添加一些代码.<br /> 2）对于copy control,constructor,destructor:若是自定义写了它们,编译器就不会生成default版本<br /> 了,但1)的代码仍旧是给你添进去的. (所以有写在private:里面这种机制)<br /> 3）constructor,destructor有栈调用默认机制;copy constructor,operator=没有，所以此两者要显式<br /> 地去调用基类的copy constructor以及operator=.<br /> */</p> <p>enum color{<br /> red,<br /> yellow,<br /> green<br /> };</p> <p>int b[3]={3,2,1};<br /> int (&p)[3]=b;</p> <p>class CShape{<br /> public:<br /> //凡是有virtual函数的类,就说明它会被多态,所以它的destructor最好也是virtual的<br /> virtual ~CShape(){}<br /> //rule of three<br /> CShape(const char* p){<br /> this->shapeName=p;<br /> }<br /> CShape(const CShape& p){<br /> shapeName=p.shapeName;<br /> }<br /> CShape& operator= (const CShape& p){<br /> if(this==&p)<br /> return *this;<br /> shapeName=p.shapeName;<br /> }</p> <p> //virtual(not pure)是继承接口以及缺省行为<br /> virtual void show();<br /> //pure virtual是只继承接口<br /> //接口继承<br /> virtual void draw()=0;<br /> //非虚拟函数的目的是让derived class继承接口以及实现<br /> //实现继承<br /> void shapeShow();<br /> void setShapeName();<br /> //static管它是不是abstract class,照样可以使用CShape::showP函数<br /> static void showP()<br /> {<br /> cout<<p[0]<<" "<<p[1]<<" "<<p[2]<<" "<<endl;<br /> }<br /> private:<br /> string shapeName;<br /> };</p> <p>void CShape::show(){<br /> cout<<this->shapeName<<endl;<br /> }<br /> void CShape::shapeShow()<br /> {<br /> cout<<this->shapeName<<endl;<br /> }<br /> void CShape::setShapeName(){<br /> shapeName="hello";<br /> }</p> <p>class Rectangle:public CShape{<br /> public:<br /> virtual ~Rectangle(){}<br /> Rectangle(const char *p):CShape("SHAPE"),rectName(p){<br /> //enum的使用<br /> //color rectColor=red;<br /> }<br /> //显式调用基类的copy constructor,operator=<br /> Rectangle(const Rectangle& p):CShape(p){<br /> rectName=p.rectName;<br /> }<br /> Rectangle& operator= (const Rectangle& p){<br /> if(this==&p)<br /> return *this;<br /> CShape::operator =(p);<br /> rectName=p.rectName;<br /> }<br /> virtual void draw();<br /> virtual void show();<br /> //即static method不可以操作nonstatic member,只能操作static member<br /> //但是倒过来,nonstatic method可以操作static member<br /> /*<br /> static void sprint(){<br /> cout<<"shape:"<<shapeshow();<br /> cout<<"rect:"<<show();<br /> }<br /> */<br /> void print(){<br /> cout<<"shape:";<br /> shapeShow();<br /> cout<<"rect:";<br /> show();<br /> }<br /> private:<br /> string rectName;<br /> };<br /> void Rectangle::draw(){<br /> cout<<"rectangle drawing"<<endl;<br /> }<br /> void Rectangle::show(){<br /> cout<<this->rectName<<endl;<br /> }</p> <p>#endif // CSHAPE_H<br />