建立一个继承figure的派生类square包含一个函数area()显示矩形面积

#include<iostream.h>
class figure
{ public:
figure(){ cout<<"基类构造函数被调用"<<endl;}
~figure(){cout<<"基类析构函数被调用"<<endl;}
void show() {cout<<"矩形面积是:"<<endl;}
};
class square:public figure
{ private:
float length,width;
public:
square ( int x,int y) { length=x; width=y;}
float area( ){ return length*width;}
};
int main()
{ square A(3,4);
A.show();
cout<<A.area()<<endl;
}