exam2_3.cpp

C++程序设计源代码例

#include "iostream.h"
const double PI =3.14; 
class Circle   //定义基类
{ 	double  radius;	
public:			
	Circle(double r) 	{ radius=r;} 	
	double CircleArea(void) {return PI*radius*radius; }  //求圆面积
};

class Rectangle  //定义基类
{
	double length,width;
public:	
	Rectangle(double x,double y){length=x,width=y;}	
	double RecArea(void){return length*width;}   //求矩形面积
};

class Graph:public Circle,public Rectangle    //定义多继承派生类
{
public:	
	Graph(double r,double x,double y):Circle(r),Rectangle(x,y)	{}	
	void ShowArea(void)     //求图形面积，调用基类成员函数
	{
		double  TotalArea; 
		TotalArea= CircleArea()+RecArea();
		cout<<"the Area of Graph is "<<TotalArea<<endl;
	}
};

void main()
{
	double x,y,r;
	cout<<"r="; cin>>r;
	cout<<"x=";	cin>>x;
	cout<<"y="; cin>>y;
	Graph g(r,x,y);
	g.ShowArea ();
}