Problem D: 平面上的点和线——Point类、Line类 (IV)

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。

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 : (0, 0) is copied.
Point : (2, -1) is copied.
Line : (0, 0) to (2, -1) is created.
Line : (1, -2) to (2, -1)
Line : (1, -2) to (0, 0)
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 (0, 0) is erased.
Point : (0, 0) 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.

AC代码

#include <iostream>
using namespace std;

class Point {
    friend class Line;
private:
    double x,y;
public:
    Point():x(0),y(0) {cout << "Point : (" << x << ", " << y << ") is created.\n";}
    Point(double x1, double y1) : x(x1), y(y1) {cout << "Point : (" << x << ", " << y << ") is created.\n";}
    void show() {cout << "Point : (" << x << ", " << y << ")\n";}
    Point(const Point &p) :x(p.x), y(p.y) {cout << "Point : (" << x << ", " << y << ") is copied.\n";}
    ~Point(){cout << "Point : (" << x << ", " << y << ") is erased.\n";}
};
class Line {
    friend class Point;
private:
    Point p, q;
public:
    Line():p(0, 0), q(0, 0){
        cout << "Line : (" << p.x << ", " << p.y << ") to (" << q.x << ", " << q.y << ") is created.\n";
    }
    Line(Point &p1, Point &q1):p(p1), q(q1) {
        cout << "Line : (" << p.x << ", " << p.y << ") to (" << q.x << ", " << q.y << ") is created.\n";
    }
    ~Line(){
        cout << "Line : (" << p.x << ", " << p.y << ") to (" << q.x << ", " << q.y << ") is erased.\n";
    }
    Line(double x1, double y1, double x2, double y2): p(x1, y1), q(x2, y2){
        cout << "Line : (" << p.x << ", " << p.y << ") to (" << q.x << ", " << q.y << ") is created.\n";
    }
    void show() {cout << "Line : (" << p.x << ", " << p.y << ") to (" << q.x << ", " << q.y << ")\n";}
    Line& SetLine(double x1, double y1, double x2, double y2) {
        p.x = x1;
        p.y = y1;
        q.x = x2;
        q.y = y2;
        return *this;
    }
};
int main()
{
    char c;
    int num, i;
    double x1, x2, y1, y2;
    Point p(1, -2), q(2, -1), t;
    t.show();
    std::cin>>num;
    Line line[num];
    for(i = 0; i < num; i++)
    {
        std::cout<<"=========================\n";
        std::cin>>x1>>c>>y1>>x2>>c>>y2;
        line[i].SetLine(x1, y1, x2, y2);
        line[i].show();
    }
    std::cout<<"=========================\n";
    Line l1(p, q), l2(p, t), l3(q, t), l4(t, q);
    l1.show();
    l2.show();
    l3.show();
    l4.show();
}