Problem E: 平面上的點——Point類 (II)

Description

在數學上，平面直角坐標系上的點用X軸和Y軸上的兩個坐標值唯一確定。現在我們封裝一個“Point類”來實現平面上的點的操作。

根據“append.cc”，完成Point類的構造方法和show()方法，輸出各Point對象的構造和析構次序。

接口描述：
Point::show()方法：按輸出格式輸出Point對象。

Input

輸入多行，每行為一組坐標“x,y”，表示點的x坐標和y坐標，x和y的值都在double數據范圍內。

Output

輸出每個Point對象的構造和析構行為。對每個Point對象，調用show()方法輸出其值：X坐標在前，Y坐標在后，Y坐標前面多輸出一個空格。每個坐標的輸出精度為最長16位。輸出格式見sample。

C語言的輸入輸出被禁用。

Sample Input

1,2

3,3

2,1

Sample Output

Point : (0, 0) is created.

Point : (1, 2) is created.

Point : (1, 2) Point : (1, 2) is erased.

Point : (3, 3) is created.

Point : (3, 3)

Point : (3, 3) is erased.

Point : (2, 1) is created.

Point : (2, 1)

Point : (2, 1) is erased.

Point : (0, 0) is copied.

Point : (1, 1) is created.

Point : (0, 0) Point : (1, 1)

Point : (0, 0) Point : (1, 1) is erased.

Point : (0, 0) is erased.

Point : (0, 0) is erased.

HINT

思考構造函數、拷貝構造函數、析構函數的調用時機。

Append Code

#include<iostream>

#include<iomanip>

using namespace std;

class Point

{

private:

????double x,y;

public:

????Point(){x=0,y=0;cout<<setprecision(16)<<"Point : (0, 0) is created.\n";}

????Point(double a,double b){x=a,y=b;cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<") is created.\n";}

????void show(){cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<")\n";}

????~Point(){cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<") is erased.\n";}

????Point(Point &a){x=0,y=0;cout<<setprecision(16)<<"Point : (0, 0) is copied.\n";}

????Point(int a){x=a,y=a;cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<") is created.\n";}

};

int main()

{

????char c;

????double a, b;

????Point q;

????while(std::cin>>a>>c>>b)

????{

????????Point p(a, b);

????????p.show();

????}

????Point q1(q), q2(1);

????q1.show();

????q2.show();

????q.show();

}