import java.awt.*;

public class Line
{
	public	point p1,p2;
	public float slope;

	Line(point P1, point P2)
	{
		if(P1.x<P2.x)
		{
		    p1=P1;
			p2=P2;
		}
		else
		{
		    p2=P1;
			p1=P2;
		}
		slope= (p2.y-p1.y)/(p2.x-p1.x);
	}

	// find a Y on the line given an x
	float YIntersect(float x)
	{
		return(slope*(x-p1.x) + p1.y);
	}

    // find an x on the line given a y
	float XIntersect(float y)
	{
		return((y -p1.y + slope*p1.x)/slope);
	}

	point Intersect(Line l2)
	{
		float xint;
		xint=((l2.p1.y- p1.y+slope*p1.x- l2.slope* l2.p1.x)/(slope-l2.slope));

		// xint is the x interception of two lines.  We need to check
		// if the actual segments intersected
		// since p1.x<=p2.x is guaranteed, we can just make sure xint is
		// between them for both lines
	   	if((p1.x<=xint && xint<=p2.x) && (l2.p1.x<=xint && xint<=l2.p2.x))
		{
		    return(new point(xint, YIntersect(xint)));
		}
		else
	    { 
		    return null;
		}
	} // Intersect

	public boolean Compare(Line l2)
	{
		return ((p1.Compare(l2.p1)) && (p2.Compare(l2.p2)) || 
				(p1.Compare(l2.p2)) && (p2.Compare(l2.p1)));
	}

	public String toString()
	{
		String s="("+p1.x+","+p1.y+") to ("+p2.x+","+p2.y+")";
		return s;
	}

	public void Swap( Line l2)
	{
		point p;

   		p=p1;
		p1=l2.p1;
		l2.p1=p;

		p=p2;
		p2=l2.p2;
		l2.p2=p;

		float x;

		if(p1.x>p2.x)
		{
	    	x=p1.x;
			p1.x=p2.x;
			p2.x=x;
		}

		if(l2.p1.x>l2.p2.x)
		{
	    	x=l2.p1.x;
			l2.p1.x=l2.p2.x;
			l2.p2.x=x;
		}


	}


} // class Line