十三周任务三

/* (程序头部注释开始)
* 程序的版权和版本声明部分
* Copyright (c) 2012, 烟台大学计算机学院学生
* All rights reserved.
* 文件名称：
* 作者：刘杨
* 完成日期： 2012 年 5 月 13 日
* 版本号： x1.0
* 对任务及求解方法的描述部分
* 输入描述：
* 问题描述：定义抽象基类Shape，由它派生出3个派生类，Circle（圆形）、Rectangle（矩形）、Triangle（三角形）。
* 程序输出：
* 程序头部的注释结束
*/

#include<iostream>
#include<string>

using namespace std;

class Shape
{
public:
virtual double area() = 0;
};
class Circle:public Shape
{
public:
Circle(double r){radius = r;}

virtual double area();
private:
double radius;
};
class Rectangle:public Shape
{
public:
Rectangle(double h,double w){height = h;width = w;}

virtual double area();
private:
double height;
double width;
};
class Triangle:public Shape
{
public:
Triangle(double d,double h){di = d; height = h;}

virtual double area();
private:
double di;
double height;
};
double Circle::area()
{
return 3.14 * radius* radius;
}
double Rectangle::area()
{
return height * width;
}
double Triangle::area()
{
return di * height / 2;
}
int main()
{
Circle c1(12.6),c2(4.9);

Rectangle r1(4.5,8.4),r2(5.0,2.5);

Triangle t1(4.5,8.4),t2(3.4,2.8);

Shape *pt[6] = {&c1,&c2,&r1,&r2,&t1,&t2};

double areas = 0.0;

for(int i = 0; i < 6; i++)
{
areas = areas + pt[i]->area();
}
cout << "totol of all areas = " << areas << endl;

system("pause");
return 0;
}