Ｃ++ Line,Point类

#include
#include

using namespace std;

class Point
{
public:
    Point(int xx = 0, int yy = 0){ _x = xx; _y = yy; };
    Point(Point &p);
    ~Point();
    int GetX(){ return _x; }
    int GetY(){ return _y; }

private:
    int _x;
    int _y;

};

Point::Point(Point &p){
    _x = p._x;
    _y = p._y;
    cout << "调用了拷贝构造函数！" << endl;
}
class Line
{
public:
    Line(Point p1,Point p2);
    Line(Line &L);
    ~Line();
    double GetLength(){ return _length; }

private:
    Point _p1, _p2;
    double _length;

};

Line::Line(Point p1, Point p2) :_p1(p1), _p2(p2){
    cout << "Line 构造函数被调用" << endl;
    double x = double(p1.GetX() - p2.GetX());
    double y = double(p1.GetY() - p2.GetY());
    _length = sqrt(x*x + y*y);
}

Line::Line(Line &L) :_p1(L._p1), _p2(L._p2){
    cout << "Line拷贝构造函数被调用" << endl;
    _length = L._length;
}
int main()
{
    Point temp1(1, 1), temp2(4, 5);//建立Point类的对象  
    Line line(temp1, temp2);
    Line line2(line);
    cout << "The length of the line is:";
    cout << line.GetLength() << endl;
    cout << "The length of the line2 is:";
    cout << line2.GetLength() << endl;
    return 0;
}