378

#include <cmath>
#include <iostream>
#include <stdio.h>

#define INF   1000000000

using namespace std;
int n;
int c=1;
double m1,m2,d,d1,d2,x1,x2,x3,x4,y_1,y2,y3,y4,c1,c2;
double px,py;

void intersect()
{
	if(x1!=x2)
		{
			m1=((y_1-y2)/(x1-x2));

		}

		else
		{
			m1=INF;

		}


		if(x3!=x4)
			m2=(y3-y4)/(x3-x4);
		else
			m2=INF;


		if(m1==INF)
		c1=0;
		else
		c1=y_1-m1*x1;

		if(m2==INF)
		c2=0;
		else
		c2=y3-m2*x3;


		if(m1==INF)
		{
			px=x1;
			if(m2==0)
			{
				py=y3;

				printf("POINT %.2lf %.2lf\n",px,py);
				return;
			}
			else
			{
				py=m2*px+c2;
				printf("POINT %.2lf %.2lf\n",px,py);
				return;
			}
		}
		if(m2==INF)
		{
			px=x3;
			if(m1==0)
			{
				py=y_1;

				printf("POINT %.2lf %.2lf\n",px,py);
				return;
			}
			else
			{
				py=m1*px+c1;
				printf("POINT %.2lf %.2lf\n",px,py);
				return;
			}
		}

		if(m1==0)
		{
			py=y_1;
			if(m2==INF)
			{
				px=x3;
				printf("POINT %.2lf %.2lf\n",px,py);
				return;
			}
			else
			{
				px=(py-c2)/m2;
				printf("POINT %.2lf %.2lf\n",px,py);
				return;
			}
		}
		if(m2==0)
		{
			py=y3;
			if(m1==INF)
			{
				px=x1;
				printf("POINT %.2lf %.2lf\n",px,py);
				return;
			}
			else
			{
				px=(py-c1)/m1;
				printf("POINT %.2lf %.2lf\n",px,py);
				return;
			}
		}

		if(m1!=m2)
		{
			px=-(c1-c2)/(m1-m2);
			py=m1*px+c1;
			printf("POINT %.2lf %.2lf\n",px,py);
		}
}

int main()
{
	cin>>n;
	cout<<"INTERSECTING LINES OUTPUT\n";
	while(n--)
	{
		cin>>x1>>y_1>>x2>>y2>>x3>>y3>>x4>>y4;
		/*
		comparing the slopes of the st. line x1y1-x2y2, x3y3-x4y4,
		st. line x1y1-x3y3, x2y2-x4y4,
		st. line x1y1-x4y4, x2y2-x3y3,
		*/
		d=(y_1-y2)*(x3-x4)-(y3-y4)*(x1-x2);
		d1=(y_1-y3)*(x2-x4)-(y2-y4)*(x1-x3);
		d2=(y_1-y4)*(x2-x3)-(y2-y3)*(x1-x4);

		if(d==0 && d1==0 && d2==0)
		{
			cout<<"LINE\n";
			continue;
		}
		else if(d==0)
		{
			cout<<"NONE\n";
			continue;
		}
		else
		{
			intersect();
		}

	}
	cout<<"END OF OUTPUT\n";
	return 0;
}

Another approach:

(but gives wa)

#include<stdio.h>


int main()
{
   printf("INTERSECTING LINES OUTPUT\n");
   int n,x_1,x_2,x_3,x_4,y_1,y_2,y_3,y_4;
   double d,d1,d2,t1,t2,x,y;

   scanf("%d",&n);


   while(n>0)
   {
      scanf("%d%d%d%d%d%d%d%d",&x_1,&y_1,&x_2,&y_2,&x_3,&y_3,&x_4,&y_4);
      d=(double)((x_1-x_2)*(y_3-y_4))-((y_1-y_2)*(x_3-x_4));
      d1=(double)((x_3-x_4)*(y_3-y_1))-((y_3-y_4)*(x_3-x_1));
      d2=(double)(-((x_3-x_1)*(y_1-y_2))+((y_3-y_1)*(x_1-x_2)));


      if((int)d==0 && (int)d1==0 && (int)d2==0)
      {
         printf("LINE\n");
      }
      else if((int)d==0)
      {
         printf("NONE\n");
      }
      else
      {
         t1=d1/d;
         t2=d2/d;
         x=x_1+t1*(x_2-x_1);
         y=y_1+t1*(y_2-y_1);
         printf("POINT %.2lf %.2lf\n",x,y);
      }
      n--;

   }

   printf("END OF OUTPUT\n");
   return 0;
}