View Code of Problem 67

#include <stdio.h>
int main(){
  float x1,y1,x2,y2,x3,y3,x4,y4,k1,k2;
  while (scanf("%d%d%d%d%d%d%d%d",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4) != EOF){
	  if(x1=x2=x3=x4)
		  printf("Yes");
     else if((x1==x2)&&(x3==x4))
      printf("No\n");
    else if((x1==x2) ||(x3==x4))
      printf("Yes\n");
      else{
        k1=(y2-y1)/(x2-x1);
    	k2=(y4-y3)/(x4-x3);
		if(k1 == k2){
			
			  if(y1-x1*((y1-y2)/(x1-x2))==y3-x3*((y3-y4)/(x3-x4)))								
					printf("Yes\n");
				else
					 printf("No\n");

		}
      	 
  
	  }
	  }
return 0;
}