2-1.cpp

用类进行图形的关系判断

#include <iostream>     
#include <cmath>   
using namespace std;
class Point                                             /*点类定义*/ 
{
    public:                                             /*外部借口，公有成员函数*/ 
        friend double Distance(Point &p,Point &q);
        Point(float xx = 0,float yy = 0)                /*构造函数*/ 
        {
            X=xx;
            Y=yy;
            cout <<"构造函数被调用Point(float xx = 0,float yy = 0)"<<endl; 
        }
        Point(Point &p)                                 /*拷贝构造函数*/
        {
            X=p.X;
            Y=p.Y;
            cout <<"拷贝构造函数被调用Point(Point &p)"<<endl; 
        }
        float GetX() {return X;}; 
        float GetY() {return Y;};
    private:                                             /*私有数据成员*/ 
        float X,Y;
};

        
double Distance(Point &p,Point &q)   
{   
    float result;   
    return sqrt((p.X-q.X)*(p.X-q.X)+(p.Y-q.Y)*(p.Y-q.Y));   
}   
//演示两点距离  
/*int main()   
{   
    Point p(0,0),q(4,3);  
    double d= distance (p,q);  
    cout << d << endl; 
    system("pause");
    return 0;
} */  
///////////////////////////////////////////////////////////////////////////////////////
class Rectangle
{
    public:                                             /*外部借口，公有成员函数*/ 
        Rectangle(Rectangle &);                         /*拷贝构造函数*/
        Rectangle(Point xp1,Point xp2);                 /*构造函数*/ 
        double GetArea(){return area;}
    private:
        Point p1,p2;
        double area;
};

Rectangle::Rectangle(Point xp1,Point xp2):p1(xp1),p2(xp2)
{
    float l=p1.GetX()>p2.GetX()?p1.GetX()-p2.GetX():p2.GetX()-p1.GetX();
    float w=p1.GetY()>p2.GetY()?p1.GetY()-p2.GetY():p2.GetY()-p1.GetY();
    cout <<"构造函数被调用Rectangle(Point xp1,Point xp2)"<<endl; 
    area = w*l;
}

Rectangle::Rectangle(Rectangle &R):p1(R.p1),p2(R.p2)
{
    area=R.area;
    cout <<"拷贝构造函数被调用Rectangle(Rectangle &)"<<endl; 
}
//演示矩形面积 
int main()   
{   
    float px,py,qx,qy;
    char temp;
    cout << "请输入两个点的坐标(px,py),(qx,qy):" << endl;
    cin >>px>>py>>qx>>qy ;
    Point myp1(px,py),myp2(qx,qy);                                 /*生成对象*/ 
    Rectangle rec(myp1,myp2);
    cout << "矩形面积为:" << rec.GetArea() << endl; 
    system("pause");
    return 0;
}