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Problem E: 平面上的点——Point类 (II)

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。现在我们封装一个“Point类”来实现平面上的点的操作。

根据“append.cc”,完成Point类的构造方法和show()方法,输出各Point对象的构造和析构次序。

接口描述:
Point::show()方法:按输出格式输出Point对象。

Input

输入多行,每行为一组坐标“x,y”,表示点的x坐标和y坐标,x和y的值都在double数据范围内。

Output

输出每个Point对象的构造和析构行为。对每个Point对象,调用show()方法输出其值:X坐标在前,Y坐标在后,Y坐标前面多输出一个空格。每个坐标的输出精度为最长16位。输出格式见sample。

C语言的输入输出被禁用。

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

思考构造函数、拷贝构造函数、析构函数的调用时机。

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();
}

Problem E: 平面上的点——Point类 (II)