【C++继承】图形类 【问题描述】 定义一个图形类(figure),其中有保护类型的成员数据：高度(height)和宽度(width)，一个公有的构造函数。由该图形类建立两个派生类：矩形类(rectangle)和等腰三角形类(triangle)。在每个派生类中都包含一个函数area（），分别用来计算矩形和等腰三角形的面积. 还有display()函数,显示对象的信息.

以下是C++的代码实现：

#include<iostream>
using namespace std;

class figure{
protected:
    int height;
    int width;
public:
    figure(int h,int w){
        height=h;
        width=w;
    }
};

class rectangle:public figure{
public:
    rectangle(int h,int w):figure(h,w){}
    int area(){
        return height*width;
    }
    void display(){
        cout<<"This is a rectangle with height "<<height<<" and width "<<width<<endl;
    }
};

class triangle:public figure{
public:
    triangle(int h,int w):figure(h,w){}
    int area(){
        return height*width/2;
    }
    void display(){
        cout<<"This is a triangle with height "<<height<<" and width "<<width<<endl;
    }
};

int main(){
    rectangle rec(3,4);
    cout<<"The area of the rectangle is "<<rec.area()<<endl;
    rec.display();

    triangle tri(3,4);
    cout<<"The area of the triangle is "<<tri.area()<<endl;
    tri.display();

    return 0;
}

运行结果：

The area of the rectangle is 12
This is a rectangle with height 3 and width 4
The area of the triangle is 6
This is a triangle with height 3 and width 4