纯虚函数与基类指针数组的运用 代码参考

#include <iostream>

using namespace std;

class Shape
{
    public:
        virtual double printArea()=0;
        virtual void printName()=0;
    
};

class Circle:public Shape
{
    private:
        double r;
    public:
        Circle(double r){this->r=r;}
        double printArea(){return 3.14159*r*r;}
        void printName()
        {
            cout<<"圆:半径="<<r<<",面积:"<<printArea()<<endl;
        }
};

class Square:public Shape
{
    private:
        double  a;
    public:
        Square(double a){this->a=a;}
        double printArea(){return a*a; }
        void printName()
        {
            cout<<"正方形:边长="<<a<<",面积:"<<printArea()<<endl;
        }
};

class Rectangle:public Shape
{
    private:
        double a,b;
    public:
        Rectangle(double a,double b){this->a=a;this->b=b;}
        double printArea(){return a*b;}
        void printName()
        {
            cout<<"长方形:长="<<a<<",宽="<<b<<",面积:"<<printArea()<<endl;
        }
};

class Trapezoid:public Shape
{
    private:
        double a,b,c;
    public:
        Trapezoid(double a,double b,double c){this->a=a;this->b=b;this->c=c;}
        double printArea(){return (a+b)*c*0.5;}
        void printName()
        {
            cout<<"梯形:上底="<<a<<",下底="<<b<<",高="<<c<<",面积:"<<printArea()<<endl;
        }
};

class Triangle:public Shape
{
    private:
        double a,b;
    public:
        
        Triangle(double a,double b){this->a=a;this->b=b;}
        double printArea(){return a*b*0.5;}
        void printName()
        {
            cout<<"三角形:底边="<<a<<",高="<<b<<",面积:"<<printArea()<<endl;
        }
};

int main()
{
    double r,x,a,b,m,n,l,s,h;
    double area=0.0;
    cin>>r>>x>>a>>b>>m>>n>>l>>s>>h;
    Shape *p[5];
    p[0]=new Circle(r);
    p[1]=new Square(x);
    p[2]=new Rectangle(a,b);
    p[3]=new Trapezoid(m,n,l);
    p[4]=new Triangle(s,h);
    for(int i=0;i<5;i++)
    {
        p[i]->printName();
        area+=p[i]->printArea();
    }
    cout<<"总面积:"<<area<<endl;
    return 0;
}