C++ 实验七多态的应用

一、要求

先建立一个Point（点）类，包含数据成员x,y（坐标点）。以它为基类，派生出一个Circle（圆）类，增加数据成员r（半径）再以Circle类为直接基类，派生出一个Cylinder（圆柱体）类，再增加数据成员h(高)

要求：

重载运算符“<<”，使之能输出一个点对象
在程序中使用虚函数和抽象类。类的层次结构的顶层是抽象基类Shape（形状）。Point（点）、Circle（圆）、Cylinder(圆柱体)都是Shape类的直接派生类和间接派生类

二、分析

由项目要求分析可知，Shape做基类，且void show()做纯虚构函数，之后Point类、Circle类、Cylinder类通过指针分别调用自己的show()函数

C++实验13

三、代码

💻提示：所有实验源码已在github整理

#include<iostream>
using namespace std;

//形状
class Shape
{
public:
	virtual void show() = 0;
};

//点类
class Point:public Shape
{
public:
	Point(){};
	Point(double x, double y)
	{
		this->x = x;
		this->y = y;
	}
	void setP(double x,double y)
	{
		this->x = x;
		this->y = y;
	}
	void show()
	{
		cout << "这是一个点" << endl;
	}
	friend ostream &operator <<(ostream &out, Point &p0);
private:
	double x, y;
	
};

ostream &operator <<(ostream &out, Point &p0)
{
	out <<"("<< p0.x<<","<<p0.y<<")";
	return out;
}

//圆类
class Circle:public Point
{
public:
	Circle() {};
	Circle(double r,double x,double y)
	{
		this->r = r;
		setP(x, y);
	}
	void setR(double r)
	{
		this->r = r;
	}
	void show()
	{
		cout << "这是一个圆" << endl;
	}
private:
	double r;
};

//圆柱类
class  Cylinder:public Circle
{
public:
	Cylinder(double x,double y,double r, double h)
	{
		setP(x, y);
		setR(r);
		this->h = h;
	}
	void show()
	{
		cout << "这是一个圆柱体" << endl;
	}
private:
	double h;
};


int main()
{
	Point p2(0, 0);
	p2.show();
	cout << "测试运算符重载  p=" << p2<< endl;

	Circle c1(2, 2, 2);
	c1.show();

	Shape * c = new Circle(3,3,3);//圆
	c->show();
	delete c;

	Shape * cy = new Cylinder(4, 4, 4, 4);//圆柱体
	cy->show();
	delete cy;

	system("pause");
	return 0;
}