class Shape //抽象类
{
public:
Shape(){cout<<"Shape"<<endl;}
virtual float getArea()=0; //纯虚函数
virtual float getPerim()=0; //纯虚函数
virtual ~Shape(){cout<<"~Shape"<<endl;} //虚析构
};
class Rectangle:public Shape
{
public:
Rectangle(float i=0,float j=0):m_i(i),m_j(j)
{
cout<<"Rectangle"<<endl;
}
float getArea()
{
return m_i*m_j;
}
float getPerim()
{
return 2*(m_i+m_j);
}
~Rectangle(){cout<<"~Rectangle"<<endl;}
private:
float m_i; //矩形的长
float m_j; //矩形的宽
};
class Circle:public Shape
{
public:
Circle(int i=0):m_k(i)
{
cout<<"Circle"<<endl;
}
float getArea()
{
return 3.14*m_k*m_k;
}
float getPerim()
{
return 3.14*2*m_k;
}
~Circle(){cout<<"~Circle"<<endl;}
private:
float m_k; //半径
};
void main()
{
Shape *p;
p=new Rectangle(4,7);
cout<<p->getArea()<<endl;
cout<<(*p).getPerim()<<endl;
delete p;
p=new Circle(9);
cout<<p->getArea()<<endl;
cout<<(*p).getPerim()<<endl;
delete p;
p=NULL;
}
运行结果：
