#include<iostream.h>const float PI=3.1416;class base{public: virtual void area() { cout<<"base::area()"<<endl;}};class Triangle:public base{private: float a,h;public: Tri 展开
#include<iostream.h>const float PI=3.1416;class base{public: virtual void area() { cout<<"base::area()"<<endl;}};class Triangle:public base{private: float a,h;public: Triangle() { cout<<"请输入三角形的底边a和高h:"<<endl;cin>>a>>h;} void area() { cout<<"三角形的面积是:"<<a*h/2<<endl;}};class Circle:public base{private: float r;public: Circle() { cout<<"请输入圆的半径r:"<<endl;cin>>r;} void area() { cout<<"圆的面积是:"<<PI*r*r<<endl;}};int main(){ base *b1,*b2;b1=new Triangle;b2=new Circle;b1->area();b2->area();return 0;}base改为抽象类时,只需将base类中的area函数定义改为:virtual void area()=0;收起
