第十週作業一

 //【任務1】在下面一段類的定義中，需要填充的函數由註釋內容給出了功能。
#include<iostream>

#include<Cmath>

using namespace std;

class Point //定義座標點類
{
public:
	double x, y;   //點的橫座標和縱座標
	Point(){x = 0; y = 0;}
	Point(double x0, double y0) {x = x0; y = y0;} 
	void PrintP(){cout << "Point:(" << x << ", " << y << ")";}
};  
class Line : public Point   //利用座標點類定義直線類, 其基類的數據成員表示直線的中點
{ 
private:
	class Point pt1, pt2;   //直線的兩個端點
public:
	Line(Point pts, Point pte);  //構造函數
	double Dx(){return pt2.x - pt1.x;}
	double Dy(){return pt2.y - pt1.y;}
	double Length();            //計算直線的長度
	void PrintL();              //輸出直線的兩個端點和直線長度
};

//構造函數，分別用參數初始化對應的端點及由基類屬性描述的中點
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());}//計算直線的長度

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();//輸出直線l的信息
	I.PrintP();//輸出直線l中點的信息
	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)
請按任意鍵繼續. . .