第3题

#include <iostream>
using namespace std;
class Point
{public:
Point(float a,float b):x(a),y(b){}
~Point(){cout<<"executing Point destructor"<<endl;}
private:
float x;
float y;
};

class Circle:public Point
{public:
Circle(int a,int b,int r):Point(a,b),radius(r){}
~Circle(){cout<<"executing Circle destructor"<<endl;}
private:
float radius;
};

int main()
{Point *p=new Circle(2.5,1.8,4.5);
Circle *pt=new Circle(2.5,1.8,4.5);
delete pt;
return 0;
}