C++(继承)

#include <iostream>
#include<string>
#include<math.h>
using namespace std;
//抽象基类
class Shape{
protected:
    string name;
public:
    Shape(string name){
        this->name=name;
    }
    void setName(string name){
        this->name=name;
    }
    string getName()const{
        return name;
    }
    //纯虚函数
    virtual double getArea()const=0;
};
class Circle :public Shape{
private:
    double radius;
public:
    Circle(string name,double radius):Shape (name){
        this->radius=radius;
    }
    void setRadius(double radius){
        this->radius=radius;
    }
    double getRadius()const{
        return radius;
    }

    virtual double getArea()const{
        return 3.14*pow(radius,2);
    }

};



class Rectangle:public Shape{
    double length;
    double width;
public:
    Rectangle(string name,double length,double width):Shape(name){
        this->length=length;
        this->width=width;

    }
    void setLength(double width){
        this->width=width;
    }
    void setWidth(double length){
        this->length=length;
    }

    double getLength()const{
        return length;
    }
    double getWidth()const{
        return width;
    }
    virtual double getArea()const{
        return length*width;
    }


};
class Triangle:public Shape{
    double base;
    double width;
public:
    Triangle(string name,double base,double width):Shape(name){
        this->base=base;
        this->width=width;
    }
    virtual double getArea()const{
        return .5*base*width;
    }

};

int main(){
    /*第一种方式  打印面积*/
  //  Shape shape("shape");
    //cout<<shape.getName()<<endl;
    puts("****************************************");
    Circle cycle("Circle",3.4);
    cycle.setName("Circle too");
    cout<<cycle.getName()<<endl;
    cout<<cycle.getRadius()<<endl;
    cout<<cycle.getArea()<<endl;
    puts("****************************************");

    Rectangle rectangle("Rectangle",4.3,2.3);
    cout<<rectangle.getName()<<endl;
    cout<<rectangle.getLength()<<endl;
    cout<<rectangle.getWidth()<<endl;
    cout<<rectangle.getArea()<<endl;
    puts("****************************************");

    Triangle triangle("triangle",4,3);
    cout<<triangle.getArea()<<endl;

    putchar(10);

    /*第二种方式  打印面积*/
    Shape*shapes[3]={
        new Circle("Circle",3.4),
        new Rectangle ("Rectangle",4.3,2.3),
        new Triangle ("triangle",4,3)
    };
    for (int i = 0; i < 3; ++i) {
        cout<<"Shape"<<i<<"\tarea:\t"<<shapes[i]->getArea()<<endl;
    }




    return 0;
}