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();
}