shape派生circle,rectangle,square

最新推荐文章于 2024-06-10 16:10:59 发布

这里是我的笔记本

最新推荐文章于 2024-06-10 16:10:59 发布

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分类专栏： c++

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本文介绍如何使用C++实现圆形、矩形和正方形的面积与周长计算，并通过函数调用进行实例演示。

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#include<iostream>//不正确代码。。
using namespace std;
const double PI=3.1415926;
class shape
{
public:
	virtual double getArea()
	{
		return -1;
	}
	virtual double getPerimeter()
	{
		return -1;
	}
};
class circle:public shape
{
	double radius;
public:
	circle(double r=0)
	{
		radius=r;
	}
	double getArea()
	{
		return PI*radius*radius;
	}
	double getPerimeter()
	{
		
		return 2*PI*radius;
	}
};
class rectangle:public shape
{
	double length;
	double width;
public:
	rectangle(double le=0,double wi=0)
	{
		length=le;
		width=wi;
	}
	double getArea()
	{
		return length*width;
	}
	double getPerimeter()
	{
		return 2*width+2*length;
	}

};
class square:public rectangle
{
	double sqlength;
public:
	square(double sq)
	{
		sqlength=sq;
	}
	double getArea()
	{
		return sqlength*sqlength;
	}
	double getPerimeter()
	{
		return 4*sqlength;
	}

};
void fun(shape* p,double *a,double *per)
{
	*a=p->getArea();
	*per=p->getPerimeter();
	
}
int main()
{
	double area,perimeter;
	shape*pp;
	
	circle r(5);
	pp=&r;
	fun(pp,&area,&perimeter);
	cout<<area<<endl;cout<<perimeter<<endl;

	rectangle b(5,6);
	pp=&b;
	fun(pp,&area,&perimeter);
	cout<<area<<endl;cout<<perimeter<<endl;

	square c(20);
	pp=&c;
	fun(pp,&area,&perimeter);
	cout<<area<<endl;cout<<perimeter<<endl;
}

#include <iostream>//转自http://blog.youkuaiyun.com/sxhelijian/article/details/7566500
using namespace std;
//定义抽象基类Shape
class Shape
{
public:
	virtual double area() const =0;            //纯虚函数
};

//定义Circle类
class Circle:public Shape
{
public:
	Circle(double r):radius(r){}                                     //结构函数
	virtual double area() const {return 3.14159*radius*radius;};   //定义虚函数
protected:
	double radius;                                                 //半径
};

//定义Rectangle类
class Rectangle:public Shape
{
public:
	Rectangle(double w,double h):width(w),height(h){}               //结构函数
	virtual double area() const {return width*height;}              //定义虚函数
protected:
	double width,height;                                           //宽与高
};

class Triangle:public Shape
{
public:
	Triangle(double w,double h):width(w),height(h){}                //结构函数
	virtual double area() const {return 0.5*width*height;}          //定义虚函数
protected:
	double width,height;                                            //宽与高
};

int main()
{
	Circle c1(12.6),c2(4.9);                                              //建立Circle类对象c1,c2,参数为圆半径
	Rectangle r1(4.5,8.4),r2(5.0,2.5);                                    //建立Rectangle类对象r1,r2,参数为矩形长、宽
	Triangle t1(4.5,8.4),t2(3.4,2.8);                                     //建立Triangle类对象t1,t2，参数为三角形底边长与高
	Shape *pt[6]={&c1,&c2,&r1,&r2,&t1,&t2};  
	//定义基类指针数组pt，使它每一个元素指向一个派生类对象
	double areas=0.0;                                                //areas为总面积
	for(int i=0;i<6;i++)
	{
		areas=areas+pt[i]->area();
	}
	cout<<"totol of all areas="<<areas<<endl;   //输出总面积
	system("pause");
	return 0;
}

#include<iostream>//比较正确的写法？
using namespace std;
const double PI=3.1415926;
class sharp
{
public:
	virtual double getArea()=0;
	
	virtual double getPerimeter()=0;
	
};
class circle:public sharp
{
	double radius;
public:
	circle(double r=0)
	{
		radius=r;
	}
	double getArea()
	{
		return PI*radius*radius;
	}
	double getPerimeter()
	{
		
		return 2*PI*radius;
	}
};
class rectangle:public sharp
{
	double length;
	double width;
public:
	rectangle(double le=0,double wi=0)
	{
		length=le;
		width=wi;
	}
	double getArea()
	{
		return length*width;
	}
	double getPerimeter()
	{
		return 2*width+2*length;
	}

};
class square:public rectangle
{
	//double sqlength;
public:
	square(double sq):rectangle(sq,sq)
	{
		//sqlength=sq;
	}
//	double getArea()
//	{
//		return sqlength*sqlength;
//	}
//	double getPerimeter()
//	{
//		return 4*sqlength;
//	}

};
void fun(sharp* p,double *a,double *per)
{
	*a=p->getArea();
	*per=p->getPerimeter();
	
}
int main()
{
	double area,perimeter;
	sharp *pp;
	
	circle r(5);
	pp=&r;
	fun(pp,&area,&perimeter);
	cout<<area<<endl;cout<<perimeter<<endl;

	rectangle b(5,6);
	pp=&b;
	fun(pp,&area,&perimeter);
	cout<<area<<endl;cout<<perimeter<<endl;

	square c(20);
	pp=&c;
	fun(pp,&area,&perimeter);
	cout<<area<<endl;cout<<perimeter<<endl;


//计算圆、矩形、正方形总面积
    double totalarea=0;
	sharp* pt[3]={&r,&b,&c};
	for(int i=0;i<3;i++)
	{
		totalarea=totalarea+pt[i]->getArea();
	}
	cout<<totalarea<<endl;
}