第十周作业一

 //【任务1】在下面一段类的定义中，需要填充的函数由注释内容给出了功能。
#include<iostream>

#include<Cmath>

using namespace std;

class Point //定义座标点类
{
public:
	double x, y;   //点的横座标和纵座标
	Point(){x = 0; y = 0;}
	Point(double x0, double y0) {x = x0; y = y0;} 
	void PrintP(){cout << "Point:(" << x << ", " << y << ")";}
};  
class Line : public Point   //利用座标点类定义直线类, 其基类的数据成员表示直线的中点
{ 
private:
	class Point pt1, pt2;   //直线的两个端点
public:
	Line(Point pts, Point pte);  //构造函数
	double Dx(){return pt2.x - pt1.x;}
	double Dy(){return pt2.y - pt1.y;}
	double Length();            //计算直线的长度
	void PrintL();              //输出直线的两个端点和直线长度
};

//构造函数，分别用参数初始化对应的端点及由基类属性描述的中点
Line :: Line(Point pts, Point pte) : Point((pts.x + pte.x) / 2, (pts.y + pte.y) / 2)
{
	pt1 = pts;
	pt2 = pte;
}

double Line :: Length(){return sqrt(Dx() * Dx() + Dy() * Dy());}//计算直线的长度

void Line :: PrintL()
{ 
	cout << " 1st ";
	pt1.PrintP();
	cout << "\n 2nd ";
	pt2.PrintP();
	cout << "\n The middle point of Line: ";
	PrintP();
	cout << "\n The Length of Line: " << Length() << endl;
}
int main()
{
	Point ps(-2, 5), pe(7, 9);
	Line I (ps, pe);
	I.PrintL();//输出直线l的信息
	I.PrintP();//输出直线l中点的信息
	cout << endl;
	system("pause");
	return 0;
}



1st Point:(-2, 5)
 2nd Point:(7, 9)
 The middle point of Line: Point:(2.5, 7)
 The Length of Line: 9.84886
Point:(2.5, 7)
请按任意键继续. . .