谭书12-5

#include<iostream>
#include<cmath>
using namespace std;
float sum=0;
float s[5];
class Shape
{public:
           virtual void printArea()const{}
           virtual void shapeName()const=0;
           
};
class Circle:public Shape
{public:
           Circle(float);
           virtual void shapeName()const{cout<<"Area of Circle is: ";}
           virtual void printArea()const;
 private:
           float radius;
};
Circle::Circle(float r)
{
    radius=r;                    
}
void Circle::printArea()const
{
    s[0]=3.14*radius*radius;
    sum+=s[0];
    cout<<s[0]<<endl;                        
}
class Rectangle:public Shape
{public:
           Rectangle(float ,float);
           virtual void shapeName()const{cout<<"Area of Rectangle is: ";}
           virtual void printArea()const;
 private:
           float length;
           float width;
};
Rectangle::Rectangle(float l,float w)
{
    length=l;
    width=w;                           
}
void Rectangle::printArea()const
{
    s[1]=length*width;
    sum+=s[1];
    cout<<s[1]<<endl;                           
}
class Triangle:public Shape
{public:
           Triangle(float ,float,float);
           virtual void shapeName()const{cout<<"Area of Rectangle is: ";}
           virtual void printArea()const;
 private:
           float a;
           float b;
           float c;                
};
Triangle::Triangle(float m,float n,float k)
{
      a=m;
      b=n;
      c=k;                         
}
void Triangle::printArea()const
{
    float p;
    p=(a+b+c)/2;
    s[2]=sqrt(p*(p-a)*(p-b)*(p-c));
    sum+=s[2];
    cout<<s[2]<<endl;                          
}
class Trapezoid:public Shape
{public:
    Trapezoid(float ,float ,float);
    virtual void shapeName()const{cout<<"Area of Trapezoid is: ";}
    virtual void printArea()const;
 private:
     float up;
     float down;
     float height;
};
Trapezoid::Trapezoid(float u,float d,float h)
{
    up=u;
    down=d;
    height=h;
}
void Trapezoid::printArea()const
{
    s[3]=0.5*(up+down)*height;
    sum+=s[3];
    cout<<s[3]<<endl;
}
class Square:public Shape
{public:
    Square(float);
    virtual void shapeName()const{cout<<"Area of Square is: ";}
    virtual void printArea()const;
 private:
     float side;    
};
Square::Square(float s)
{
    side=s;
}
void Square::printArea()const
{
    s[4]=side*side;
    sum+=s[4];
    cout<<s[4]<<endl;
}
int main()
{
    Circle c(10);
    Rectangle r(5,2);
    Triangle t(3,2,4);
    Trapezoid z(1,2,3);
    Square s(5);
    Shape *p[5];
    int i;
    p[0]=&c;
    p[0]->shapeName();
    p[0]->printArea();
    p[1]=&r;
    p[1]->shapeName();
    p[1]->printArea();
    p[2]=&t;
    p[2]->shapeName();
    p[2]->printArea();
    p[3]=&z;
    p[3]->shapeName();
    p[3]->printArea();
    p[4]=&s;
    p[4]->shapeName();
    p[4]->printArea();
    cout<<"The total area is: "<<sum<<endl;
    return 0;
}