/*
* Copyright (c) 2014,
* All rights reserved.
* :
* :2014 5 28
* :v1.0
* :
* :
* 】 , Shape, 3 ,
*Circle( )、Rectangle( )、Triangle( )。 main() ,
* 。
* :
* :
* :
*/
#include <iostream>
#define pi 3.14
using namespace std;
class Shape
{
public:
virtual float area()const =0;
};
class Circle:public Shape
{
public:
Circle(float ra):r(ra){}
virtual float area()const;
protected:
float r;
};
float Circle::area()const
{return pi*r*r;}
class Rectangle:public Shape
{
public:
Rectangle(float a,float b):l(a),m(b){}
virtual float area()const;
float l,m;
};
float Rectangle::area()const
{return l*m;}
class Triangle:public Shape
{
public:
Triangle(float l1,float m1):a1(l1),b1(m1){}
virtual float area()const
{
return a1*b1;
}
private:
float a1,b1;
};
int main()
{
Circle c1(12.6),c2(4.9);// Circle c1,c2,
Rectangle r1(4.5,8.4),r2(5.0,2.5);// Rectangle r1,r2, 、
Triangle t1(4.5,8.4),t2(3.4,2.8); // Triangle t1,t2,
Shape *pt[6]= {&c1,&c2,&r1,&r2,&t1,&t2}; // pt,
double areas=0.0; //areas
for(int i=0; i<6; i++) // , , , !!!!
{
areas=areas + pt[i]->area();
}
cout<<"totol of all areas="<<areas<<endl; //
return 0;
}