定义点类和直线类，计算两条直线的交点

定义点类和直线类，计算两条直线的交点。

要求利用 Point 的组合完成 class Line ，也就是说需要利用两个点构成一条直线；

其次题目保证两直线必定相交，也就是说我们直接利用公式求解即可；

代码如下：

#include<iostream>

using namespace std;

class Point
{
    private:
        double x , y;
    public:
        Point(double x_ = 0, double y_ = 0):x(x_),y(y_) {}
        Point(const Point & rhs);
        ~Point();
        Point & operator = (const Point & rhs);
        friend ostream & operator <<(ostream & os , const Point & rhs);
        friend class Line;
};

Point::Point(const Point & rhs)
{
    if(this != &rhs)
    {
        x = rhs.x;
        y = rhs.y;
    }
}

Point::~Point()
{
    cout<<"~ ~ ~Point X , Y "<<x<<" , "<<y<<endl;
}

Point & Point::operator = (const Point & rhs)
{
    x = rhs.x; 
    y = rhs.y; 
    return (*this);
} 

ostream & operator <<(ostream & os , const Point & rhs)
{
    os<<"("<<rhs.x<<" , "<<rhs.y<<")"<<endl;
    return (os);
}

class Line
{
    private:
        Point point0 , point1 ;
    public:
        Line(double x0 = 0,double y0 = 0,double x1 = 0,double y1 = 0):point0(x0,y0),point1(x1,y1) { }
        Line(const Line & rhs);
        ~Line();
        Point Jiaodian(const Line zhi1);
};

Line::Line(const Line & rhs)
{
    if(this != &rhs)
    {
        point0 = rhs.point0;
        point1 = rhs.point1;
    }
}

Line::~Line() 
{
    cout<<"~ ~ ~Line Point0 , Point1"<<endl;
}

Point Line::Jiaodian( const Line zhi1)
{
    double a0,a1,b0,b1,c0,c1;
    double xx , yy ;
    a0 = point1.x - point0.x;
    b0 = point1.y - point0.y;
    c0 = point0.y*point1.x - point1.y*point0.x;
    a1 = zhi1.point1.x - zhi1.point0.x;
    b1 = zhi1.point1.y - zhi1.point0.y;
    c1 = zhi1.point0.y*zhi1.point1.x - zhi1.point1.y*zhi1.point0.x;
    xx = (c1*a0 - c0*a1)/(b0*a1 - a0*b1);
    yy = (c0*b1 - c1*b0)/(a0*b1 - a1*b0);
    return   Point(xx , yy);
}

int main()
{  
    int a,b,c,d;
    cin>>a>>b>>c>>d; 
    Line L1(a,b,c,d) ;
    cin>>a>>b>>c>>d;
    Line L2(a,b,c,d) ;
    Point aa = L1.Jiaodian(L2); 
    cout<<"交点为 ："<<aa;
    return 0;
}

测试例子：

0 0 2 2

0 2 2 0

输出：

~ ~ ~Line Point0 , Point1

~ ~ ~Point X , Y 2 , 0

~ ~ ~Point X , Y 0 , 2

交点为 ：(1 , 1)

~ ~ ~Point X , Y 1 , 1

~ ~ ~Line Point0 , Point1

~ ~ ~Point X , Y 2 , 0

~ ~ ~Point X , Y 0 , 2

~ ~ ~Line Point0 , Point1

~ ~ ~Point X , Y 2 , 2

~ ~ ~Point X , Y 0 , 0