十三周任务3

#include<iostream>      
#include<Cmath>      
using namespace std;  
const double pi=3.1415926;    
class Shape //定义抽象基类   
{  
public:  
    virtual double areas()=0;  
};  
    
class Circle: public Shape   //利用抽象基类定义圆类      
{    
public:    
    Circle(double Circle_radius);//构造函数      
    ~Circle(){}   
    double areas();  
private:    
    double Circle_radius;    
}; 
  
class Rectangle: public Shape    //利用抽象基类定义矩形类        
{    
public:    
    Rectangle(double Rectangle_long,double Rectangle_wide);//构造函数      
    ~Rectangle(){}    
    double areas();    
private:    
    double Rectangle_long;    
    double Rectangle_wide;    
};   
  
class Triangle: public Shape  //利用抽象基类定义三角形类      
{    
public:    
    Triangle(double Triangle_bottom,double Triangle_high); //构造函数      
    ~Triangle(){}    
    double areas();   
private:    
    double Triangle_bottom;  
    double Triangle_high;    
};  
Circle::Circle(double Circle_radius)//构造函数   
{  
    this->Circle_radius=Circle_radius;  
}  
double Circle::areas()  
{  
return (pi*Circle_radius*Circle_radius);  
}  
Rectangle::Rectangle(double Rectangle_long,double Rectangle_wide)  
{  
    this->Rectangle_long=Rectangle_long;  
    this->Rectangle_wide=Rectangle_wide;  
}  
double Rectangle::areas()  
{  
    return (Rectangle_long*Rectangle_long);  
}  
Triangle::Triangle(double Triangle_bottom,double Triangle_high)  
{  
    this->Triangle_bottom=Triangle_bottom;  
    this->Triangle_high=Triangle_high;  
}  
double Triangle::areas()   
{  
    return (Triangle_bottom*Triangle_high/2);  
}  
  
int main()  
{  
    Circle c1(12.6),c2(4.9);    //建立Circle类对象c1,c2,参数为圆半径   
    Rectangle r1(4.5,8.4),r2(5.0,2.5);       //建立Rectangle类对象r1,r2,参数为矩形长、宽   
    Triangle t1(4.5,8.4),t2(3.4,2.8);    //建立Triangle类对象t1,t2，参数为三角形底边长与高   
    Shape *pt[6]={&c1,&c2,&r1,&r2,&t1,&t2}; //定义基类指针数组pt，各元素指向一个派生类对象   
    double areas=0.0;      //areas为总面积   
    for(int i=0; i<6; i++)  
    {  
        areas=areas+pt[i]->areas();  
    }  
    cout<<"totol of all areas="<<areas<<endl;   //输出总面积   
    system("pause");  
    return 0;  
}