题目要求如下:
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代码如下:
/*
* Copyright (c) 2013, 烟台大学计算机学院
* All rights reserved.
* 作 者: 沈远宏
* 完成日期:2014 年06月19日
* 版 本 号:v1.0
* 问题描述:Description
编写一个程序,声明抽象基类Shape,由它派生出3个派生类: Circle(圆形)、Rectangle(矩形)、Triangle(三角形),用一个函数printArea分别输出以上三者的面积(结果保留两位小数),3个图形的数据在定义对象时给定。
Input
圆的半径
矩形的边长
三角形的底与高
Output
圆的面积
矩形的面积
三角形的面积
*/
#include <iostream>
#include <iomanip>
#define PI 3.1415926
using namespace std;
class Shape
{
public:
virtual double Area()=0;
};
class Circle:virtual public Shape
{
protected:
double r;
double c_area;
public:
Circle(double rr):r(rr){}
double Area()
{
return c_area=PI*r*r;
}
};
class Rectangle:virtual public Shape
{
protected:
double width;
double length;
double c_area;
public:
Rectangle(double ww,double ll):width(ww),length(ll){}
double Area()
{
c_area=width*length;
return c_area;
}
};
class Triangle:virtual public Shape
{
protected:
double width;
double height;
double c_area;
public:
Triangle(double ww,double hh):width(ww),height(hh){}
double Area()
{
c_area=width*height/2;
return c_area;
}
};
void printArea(Circle c)
{
cout<<c.Area()<<endl;
}
void printArea(Rectangle c)
{
cout<<c.Area()<<endl;
}
void printArea(Triangle c)
{
cout<<c.Area()<<endl;
}
//主函数已给定如下,提交时不需要包含,会自动添加到程序尾部
int main()
{
float r,a,b,w,h;
cout<<fixed<<setprecision(2);
cin>>r;
Circle circle(r);
cout<<"area of circle = ";
printArea(circle);
cin>>a>>b;
Rectangle rectangle(a,b);
cout<<"area of rectangle = ";
printArea(rectangle);
cin>>w>>h;
Triangle triangle(w,h);
cout<<"area of triangle = ";
printArea(triangle);
return 0;
}
运行结果:
OJ要求结果输出例样: