C++面向对象实验（四）

实验6 虚基类与抽象类

#include
#include
#include
#include
#include
#include
#include
#include
#include
using namespace std; 
class shape 
{
  public: 
   virtual float Getarea()=0; 
   
}; 

class Rectangle:public shape 
{
  public: 
	Rectangle(float a,float b):shape()
	{
	   xx=a; yy=b;
    }; 
	float Getarea()
	{
	   return xx*yy;
	} 
	private: 
	float xx,yy; 
}; 

class circle:public shape 
{
   public: 
	circle(float c):shape()
	{
		r=c;
	}; 
	float Getarea()
	{
	 return 3.14*r*r;
	}; 
    private: 
	float r;
}; 

int main() 
{ 
     float x,y,z;
     cin>>x>>y;    //长方形 
     Rectangle a(x,y); 
     cout<>z; 
     circle b(z);   //圆 
     cout<

#include
#include
#include
#include
#include
#include
#include
#include
#include
using namespace std; 
class Shape{ 
	public: 
	Shape(double x) 
	{ 
    	r=x; 
	} 
	virtual void area()=0; 
	virtual void perimeter()=0; 
	protected: 
 	double r; 
}; 
class Circle:public Shape{ 
		public: 
        Circle (double x):Shape(x) 
         {} 
  void area() 
  { 
   cout<<"圆的面积是:"<<3.14*r*r<area();
 ptr->perimeter(); 
 ptr=&ob2; 
 ptr->area(); 
 ptr->perimeter(); 
 ptr=&ob3; 
 ptr->area(); 
 ptr->perimeter(); 
 return 0; 
}