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.cc
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();
}
答案
#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."<<endl;
}
Point(int _x,int _y)
{
x = _x;
y = _y;
cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<")is created."<<endl;
}
Point(int _x)
{
x=_x;
y=_x;
cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<")is copied."<<endl;
}
~Point ()
{
cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<")is erased."<<endl;
}
Point(Point const &p)
{
x=p.x;
y=p.y;
cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<")is copied."<<endl;
}
void show()
{
cout<<setprecision(16)<<"Point : ("<<x<<", "<<y<<")"<<endl;
}
};