平面上的点——Point类 (III)

Posted by 可乐 on March 5, 2017
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);
	}