平面上的点——Point类 (III)

Problem A: 平面上的点——Point类 (III)

Time Limit: 1 Sec  Memory Limit: 4 MB
Submit: 4073  Solved: 2785
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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。实现showPoint()函数。

接口描述：
showPoint()函数按输出格式输出Point对象，调用Point::show()方法实现。
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。showPoint()函数用来输出（通过参数传入的）Point对象的值：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) is copied.
Point : (1, 2)
Point : (1, 2) is erased.
Point : (1, 2) is erased.
Point : (3, 3) is created.
Point : (3, 3) is copied.
Point : (3, 3)
Point : (3, 3) is erased.
Point : (3, 3) is erased.
Point : (2, 1) is created.
Point : (2, 1) is copied.
Point : (2, 1)
Point : (2, 1) is erased.
Point : (2, 1) is erased.
Point : (0, 0) is copied.
Point : (1, 1) is created.
Point : (0, 0) is copied.
Point : (1, 1) is copied.
Point : (0, 0) is copied.
Point : (0, 0)
Point : (1, 1)
Point : (0, 0)
Point : (0, 0) is erased.
Point : (1, 1) is erased.
Point : (0, 0) is erased.
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

代码如下：

    #include<iostream>  
    #include<iomanip>  
    using namespace std;  
    class Point{  
    private:  
        double x;  
        double y;  
    public:  
        Point():x(0),y(0){cout<<setprecision(16)<<"Point : (0, 0) is created."<<endl;}  
        Point(double a,double b):x(a),y(b){cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<") is created."<<endl;}  
        Point(double a):x(a),y(1){cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<") is created."<<endl;}  
        void show();  
        ~Point()  
        {  
            cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<") is erased."<<endl;  
        }  
        Point(const Point &p)  
        {  
            x=p.x;  
            y=p.y;  
            cout<<setprecision(16)<<"Point : ("<<p.x<<", "<<p.y<<") is copied."<<endl;  
        }  
    };  
    void Point::show()  
    {  
           cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<")"<<endl;  
    }  
      
    void showPoint(Point a)  
        {  
             a.show();  
        }  
      
    void showPoint(Point a,Point b,Point c)  
        {  
             a.show();  
             b.show();  
             c.show();  
        }  
    int main()
    {
        char c;
        double a, b;
        Point q;
        while(std::cin>>a>>c>>b)
        {
            Point p(a, b);
            showPoint(p);
        }
        Point q1(q), q2(1);
        showPoint(q1, q2, q);
    }