Intersection of Random Two Lines From a Set of N Lines

#include<stdio.h>
#include<ctype.h>
#include<conio.h>
#include<stdlib.h>
 
int i=0; 
	int a1=0 , b1=0 ,c1=0;
	int detA =0 , det1 =0 , det2=0 ; int l1=0 ,l2=0;
	float  x=0,y=0 ; int lines ;int p=0,q=0,r=0,s=0;
	struct COF {
                 int a =0,b=0,c=0,k=0;
                 int count =0;
                 struct COF *next;
	};
 
	COF AccessLine(COF *A,int m)
	   {
 
			do 
			{
				if(A->count==m-1) { return *A; }
 
			 else { A=A->next ; }
			}
 
			while(A->next->count!=1);
 
 
 
	   }
 
int main(void)
 
{
 
 
	struct COF *P;
	P=(COF *) malloc(sizeof(COF));
	struct COF *REF;
	REF=(COF *) malloc(sizeof(COF));
	REF=P;
 
 
 
	printf("Number of lines N= ");
	scanf("%d",&lines);
 
 
 
    for ( i=0;i<lines ; i++ )
 
	{
	printf("Enter the Coficients of  %d th   line \n", i+1 );
	printf("Enter a[%d] = ", i);
	scanf("%d",&a1);
	printf("Enter b[%d] = ",i);
	scanf("%d",&b1);
	printf("Enter c[%d] = ",i);
	scanf("%d", &c1);
	P->a=a1; P->b=b1;P->c=c1 ;P->k=-1*c1;P->count=i;
	a1=0 ; b1=0 ;c1=0;
	P->next=(COF *) malloc(sizeof(COF));
	if(i==lines-1) { P->next=REF;}
	  else { printf("VALUE OF i is %d : \n",i); P=P->next;}
 
		}	
 
      printf("CIRCULAR LINKED LIST OR COEFICIENT LIST IS CREATED :PREE ANY LEY ... \n ");
 
      getch();
      printf("ENTER THE LINE NUMBER FOR LINE1 IN BETWEEN 1 AND %d : ",lines);
      scanf("%d",&l1);
      printf("ENTER THE LINE NUMBER FOR LINE2 IN BETWEEN 1 AND %d :  ",lines);
      scanf("%d",&l2);
 
      COF *LINE1=(COF *) malloc(sizeof(COF));
      COF *LINE2=(COF *) malloc (sizeof(COF));
      P=REF;
	  *LINE1=AccessLine(P,l1);
	  P=REF;
      *LINE2=AccessLine(P,l2);
      printf("SUCESS .. PRESS ANY KEY ... : \n");getch();
	    printf("A line is  is   %d x + %d y + %d  =0 : \n ",LINE1->a,LINE1->b,LINE1->c);  
	    printf("A line is  is   %d x + %d y + %d  =0 : \n ",LINE2->a,LINE2->b,LINE2->c); 
 
		printf("CALCULATING INTERSECTION : \n");
		detA= LINE1->a*LINE2->b - LINE1->b*LINE2->a;
		det1=LINE1->a*LINE2->k - LINE2->a*LINE1->k ;
		det2=LINE2->b*LINE1->k - LINE1->b*LINE2->k;
		x=float(det2)/float(detA);
		y=float(det1)/float(detA);
 
		printf("INTERSECTION OF LINES %d &  %d IS : X CORD = %f  ,  Y CORD %f  :\n",l1,l2,x,y);      
      printf("END OF CODE : PRES ANY KEY ...... : ");
 
	getch();
 
	return(0);	
}