Description
在数学上，平面直角坐标系上的点用X轴和Y轴上的两个坐标值唯一确定，两点确定一条线段。现在我们封装一个“Point类”和“Line类”来实现平面上的点的操作。
根据“append.cc”，完成Point类和Line类的构造方法和show()方法，输出各Line对象和Point对象的构造和析构次序。
接口描述：
Point::show()方法：按格式输出Point对象。
Line::show()方法：按格式输出Line对象。
Line::SetLine(double, double, double, double)方法：设置Line对象起点的x,y坐标（第一个和第二参数）和终点的x,y坐标（第三个和第四个坐标），并返回本对象
Line::SetLine(const Point &, const Point &)方法：设置Line对象的起点（第一个参数）和终点（第二个坐标），并返回本对象
Line::SetLine(const Line&)方法：设置Line对象，复制参数的坐标，并返回本对象
Line::readLine()方法：从标准输入上读入坐标，格式见Sample
Input
输入的第一行为N，表示后面有N行测试样例。
每行为两组坐标“x,y”，分别表示线段起点和终点的x坐标和y坐标，两组坐标间用一个空格分开，x和y的值都在double数据范围内。
Output
输出为多行，每行为一条线段，起点坐标在前终点坐标在后，每个点的X坐标在前，Y坐标在后，Y坐标前面多输出一个空格，用括号包裹起来。输出格式见sample。
C语言的输入输出被禁用。
Sample Input
4 0,0 1,1 1,1 2,3 2,3 4,5 0,1 1,0
Sample Output
Point : (1, -2) is created.
Point : (2, -1) is created.
Point : (0, 0) is created.
Point : (0, 0)
Point : (0, 0) is created.
Point : (0, 0) is created.
Line : (0, 0) to (0, 0) is created.
Point : (0, 0) is created.
Point : (0, 0) is created.
Line : (0, 0) to (0, 0) is created.
Point : (0, 0) is created.
Point : (0, 0) is created.
Line : (0, 0) to (0, 0) is created.
Point : (0, 0) is created.
Point : (0, 0) is created.
Line : (0, 0) to (0, 0) is created.
Line : (0, 0) to (1, 1)
Line : (1, 1) to (2, 3)
Line : (2, 3) to (4, 5)
Line : (0, 1) to (1, 0)
Point : (1, -2) is copied.
Point : (2, -1) is copied.
Line : (1, -2) to (2, -1) is created.
Point : (1, -2) is copied.
Point : (0, 0) is copied.
Line : (1, -2) to (0, 0) is created.
Point : (2, -1) is copied.
Point : (0, 0) is copied.
Line : (2, -1) to (0, 0) is created.
Point : (1, -2) is copied.
Point : (2, -1) is copied.
Line : (1, -2) to (2, -1) is copied.
Line : (1, -2) to (2, -1)
Line : (1, -2) to (2, -1)
Line : (2, -1) to (0, 0)
Line : (0, 0) to (2, -1)
Line : (0, 0) to (2, -1) is erased.
Point : (2, -1) is erased.
Point : (0, 0) is erased.
Line : (2, -1) to (0, 0) is erased.
Point : (0, 0) is erased.
Point : (2, -1) is erased.
Line : (1, -2) to (2, -1) is erased.
Point : (2, -1) is erased.
Point : (1, -2) is erased.
Line : (1, -2) to (2, -1) is erased.
Point : (2, -1) is erased.
Point : (1, -2) is erased.
Line : (0, 1) to (1, 0) is erased.
Point : (1, 0) is erased.
Point : (0, 1) is erased.
Line : (2, 3) to (4, 5) is erased.
Point : (4, 5) is erased.
Point : (2, 3) is erased.
Line : (1, 1) to (2, 3) is erased.
Point : (2, 3) is erased.
Point : (1, 1) is erased.
Line : (0, 0) to (1, 1) is erased.
Point : (1, 1) is erased.
Point : (0, 0) is erased.
Point : (0, 0) is erased.
Point : (2, -1) is erased.
Point : (1, -2) is erased.
HINT
Append Code
#include <iostream>
using namespace std;
class Point
{
friend class Line;
private:
double x;
double y;
public:
Point(double _x=0,double _y=0):x(_x),y(_y){cout<<"Point : ("<<x<<", "<<y<<") is created."<<endl;}
void show(){cout<<"Point : ("<<x<<", "<<y<<")"<<endl;}
~Point(){cout<<"Point : ("<<x<<", "<<y<<") is erased."<<endl;}
Point(const Point&p)
{
x=p.x;
y=p.y;
cout<<"Point : ("<<x<<", "<<y<<") is copied."<<endl;
}
};
class Line
{
friend class Point;
private:
Point A;
Point B;
public:
Line(double x1=0,double y1=0,double x2=0,double y2=0):A(x1,y1),B(x2,y2){cout<<"Line : ("<<A.x<<", "<<A.y<<") to ("<<B.x<<", "<<B.y<<") is created."<<endl;}
void show(){cout<<"Line : ("<<A.x<<", "<<A.y<<") to ("<<B.x<<", "<<B.y<<")"<<endl;}
~Line()
{
cout<<"Line : ("<<A.x<<", "<<A.y<<") to ("<<B.x<<", "<<B.y<<") is erased."<<endl;
}
Line(Point&p, Point&q):A(p),B(q)
{
cout<<"Line : ("<<A.x<<", "<<A.y<<") to ("<<B.x<<", "<<B.y<<") is created."<<endl;
}
Line (const Line&cc):A(cc.A),B(cc.B)
{
cout<<"Line : ("<<A.x<<", "<<A.y<<") to ("<<B.x<<", "<<B.y<<") is copied."<<endl;
}
void readLine ()
{
double x1,y1,x2,y2;
char a;
std::cin>>x1>>a>>y1>>x2>>a>>y2;
A.x=x1;
A.y=y1;
B.x=x2;
B.y=y2;
}
Line &setLine(const Line &p)
{
A=p.A;
B=p.B;
return *this;
}
Line &setLine(const Point &_A,const Point &_B)//:A(_A),B(_B)
{
A=_A;
B=_B;
return *this;
}
};
int main()
{
int num, i;
Point p(1, -2), q(2, -1), t;
t.show();
std::cin>>num;
Line line[num];
for(i = 0; i < num; i++)
{
line[i].readLine();
line[i].show();
}
Line l1(p, q), l2(p,t), l3(q,t), l4(l1);
l1.show();
l2.setLine(l1).show();
l3.show();
l4.setLine(t,q).show();
}