《C++第十二周实验报告4-1》---类的组合与继承

/*
【任务4】类的组合与继承
（1）先建立一个Point(点)类，包含数据成员x,y(坐标点)；
（2）以Point为基类，派生出一个Circle(圆)类，增加数据成员(半径)，基类的成员表示圆心；
（3）编写上述两类中的构造、析构函数及必要的输入输出函数
（4）定义友元函数int locate，判断点p在圆c上、圆c内或圆c外，返回值<0圆内，==0圆上，>0 圆外；
（5）重载关系运算符（6种）运算符，使之能够按圆的面积比较两个圆的大小；
（6）给定一点p，求出该点与圆心相连成的直线与圆的两个交点并输出
*/
/* (程序头部注释开始)
* 程序的版权和版本声明部分
* Copyright (c) 2011, 烟台大学计算机学院学生 
* All rights reserved.
* 文件名称：  vehicle.cpp                            
* 作    者：   计114-3 王兴锋     
* 完成日期：    2012  年   5    月    7    日
* 版 本 号：       V 1.0
*/
#include <iostream>
#include <cmath>

using namespace std;

#define PI 3.1415926
//自行定义类
class Point //定义坐标点类
{ 
public:
	double x, y;//点的横坐标和纵坐标
	Point(){x = 0; y = 0;}
	~Point(){}
	Point(double x0, double y0) {x = x0; y = y0;}
	void setXY(double x0, double y0){x = x0; y = y0;}
	double getX(){return x;}
	double getY(){return y;}
	friend ostream& operator << (ostream&, Point&);
	friend istream& operator >> (istream&, Point&);
};
ostream& operator << (ostream& output, Point& p)
{
	output << "(" << p.x << "," << p.y << ")" << endl;

	return output;
}
istream& operator >> (istream& input, Point& p) 
{
	cout << "输入点的横纵坐标：（x y）";
	input >> p.x >> p.y;

	return input;
}
class Circle : public Point
{
protected:
	double r;
public:
	Circle(){}
	Circle(double x, double y, double r = 0):Point(x, y){this->r = r;}
	~Circle(){}
	void setR(double r){this->r = r;}
	double getR(){return r;}
	double getL(){return 2*PI*r;}
	double getAre(){return PI*r*r/2;}
	friend ostream& operator << (ostream&, Circle&);
	friend istream& operator >> (istream&, Circle&);
	friend double locate(Point p, Circle c);
	bool operator > (Circle &c);
	bool operator < (Circle &c);
	bool operator >= (Circle &c);
	bool operator <= (Circle &c);
	bool operator == (Circle &c);
	bool operator != (Circle &c);
	void crossover_point1(Point p, Circle c, Point &p1, Point &p2);
};
void crossover_point1(Point p, Circle c, Point &p1, Point &p2)
{
	double len = c.getR()/(locate(p, c) + c.getR());
	double x = (p.x-c.x)*len;
	double y = (p.y-c.y)*len;

	p1.x = c.x + x;
	p1.y = c.y + y;
	p2.x = c.x - x;
	p2.y = c.y - y;
}
bool Circle::operator > (Circle &c)
{
	if (getAre() > c.getAre())
		return true;
	else
		return false;
}
bool Circle::operator < (Circle &c)
{
	if (getAre() < c.getAre())
		return true;
	else
		return false;
}
bool Circle::operator >= (Circle &c)
{
	if (getAre() >= c.getAre())
		return true;
	else
		return false;
}
bool Circle::operator <= (Circle &c)
{
	if (getAre() <= c.getAre())
		return true;
	else
		return false;
}
bool Circle::operator == (Circle &c)
{
	if (getAre() == c.getAre())
		return true;
	else
		return false;
}
bool Circle::operator != (Circle &c)
{
	if (getAre() != c.getAre())
		return true;
	else
		return false;
}
double locate(Point p, Circle c)
{
	return (sqrt((c.x - p.x)*(c.x - p.x) + (c.y - p.y)*(c.y - p.y)) - c.r);
}
ostream& operator << (ostream& out, Circle& c)
{
	out << "圆心：" << "(" << c.x << "," << c.y << ")" << endl;
	out << "半径：" << c.r << endl;

	return out;
}
istream& operator >> (istream& in, Circle& c)
{
	cout << "输入圆心坐标：（x y）";
	in >> c.x >> c.y;
	cout << "请输入圆的半径：（r）" ;
	in >> c.r;

	return in;
}
//用下面的main()函数测试
int main( )
{
	Circle c1(3,2,4),c2(4,5,5);      //c2应该大于c1
	Point p1(1,1),p2(3,-2),p3(7,3);  //分别位于c1内、上、外

	cout<<"圆c1: "<<c1;
	cout<<"点p1: "<<p1;
	cout<<"点p1在圆c1之"<<((locate(p1, c1)>0)?"外":((locate(p1, c1)<0)?"内":"上"))<<endl;
	cout<<"点p2: "<<p2;
	cout<<"点p2在圆c1之"<<((locate(p2, c1)>0)?"外":((locate(p2, c1)<0)?"内":"上"))<<endl;	
	cout<<"点p3: "<<p3;
	cout<<"点p3在圆c1之"<<((locate(p3, c1)>0)?"外":((locate(p3, c1)<0)?"内":"上"))<<endl;
	cout<<endl; 

	cout<<"圆c1: "<<c1;
	if(c1>c2) cout<<"大于"<<endl;
	if(c1<c2) cout<<"小于"<<endl; 
	if(c1>=c2) cout<<"大于等于"<<endl;
	if(c1<=c2) cout<<"小于等于"<<endl; 
	if(c1==c2) cout<<"等于"<<endl; 
	if(c1!=c2) cout<<"不等于"<<endl; 
	cout<<"圆c2: "<<c1;
	cout<<endl; 

	Point p4,p5;
	crossover_point1(p1,c1, p4, p5);

	cout<<"点p1: "<<p1;
	cout<<"与圆c1: "<<c1;
	cout<<"的圆心相连，与圆交于两点，分别是："<<endl;
	cout<<"交点: "<<p4;
	cout<<"交点: "<<p5;
	cout<<endl; 

	system("pause");
	return 0;
}
/*
圆c1: 圆心：(3,2)
半径：4
点p1: (1,1)
点p1在圆c1之内
点p2: (3,-2)
点p2在圆c1之上
点p3: (7,3)
点p3在圆c1之外

圆c1: 圆心：(3,2)
半径：4
小于
小于等于
不等于
圆c2: 圆心：(3,2)
半径：4

点p1: (1,1)
与圆c1: 圆心：(3,2)
半径：4
的圆心相连，与圆交于两点，分别是：
交点: (-0.577709,0.211146)
交点: (6.57771,3.78885)

请按任意键继续. . .
*/