OJ 嘻唰唰抽象基类

来源：互联网发布：斗鱼登录网络异常编辑：程序博客网时间：2024/05/22 12:27

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

Sample Input

12.64.5 8.44.5 8.4

Sample Output

area of circle = 498.76area of rectangle = 37.80area of triangle = 18.90

代码：

#include <iostream>#include <iomanip>using namespace std;class Shape{public:    virtual void Area()=0;};class Circle:public Shape{public:    Circle(double r):radius(r) {}   void Area()    {        cout<<3.1415916*radius*radius<<endl;    }private:    double radius;};class Rectangle:public Shape{public:    Rectangle(double w,double l):width(w),longth(l) {}   void Area()    {        cout<<width*longth<<endl;    }private:    double width;    double longth;};class Triangle:public Shape{public:    Triangle(double b,double h):base(b),height(h) {}    void Area()    {       cout<<base*height/2<<endl;    }private:    double base;    double height;};void printArea(Shape &s){    s.Area();}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：

0 0