Problem E: 平面上的点——Point类 (II)

Posted 2020-09-04 TogetherLaugh

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();

}