View Code of Problem 67

# include<stdio.h>
int main(void)
{
	float x1,y1,x2,y2,x3,y3,x4,y4,k1,k2;
	while(scanf("%f%f%f%f%f%f%f%f",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4)!=EOF)
	{
		if(x1!=x2&&x4!=x3)
		{
			k1 = (y2-y1)/(x2-x1);
			k2 = (y4-y3)/(x4-x3);
			if(k1!=k2)
			{
				printf("Yes\n");
			}
			else if(y1-k1*x1!=y3-k2*x3)
			{
				printf("No\n");
			}
			else
			{
				printf("Yes\n");
			}
		}
		else if(x1==x2&&x3==x4&&x1!=x3)
		{
			printf("No\n");
		}
		else
		{
			printf("Yes\n");
		}
	}
	return 0;
}