View Code of Problem 67

#include<stdio.h>
#include<math.h>
int main()
{
	float x1, x2, x3, x4, y1, y2, y3, y4, k1, k2, b1, b2;
	while(scanf("%f %f %f %f %f %f %f %f", &x1, &y1, &x2, &y2, &x3, &y3, &x4, &y4)!=EOF)
	{
		if(x1 == x2 && x3 == x4)
		{
			if(x1 == x3)
				printf("Yes\n");
			else
				printf("No\n");
		}
		else
		{
		k1 = (y1 - y2) / (x1 - x2);
		k2 = (y3 - y4) / (x3 - x4);
		b1 = y1 - k1 * x1;
		b2 = y3 -k2 * x3;
		if(k1 == k2 && b1 != b2)
			printf("No\n");
		else
			printf("Yes\n");
		}
	}
}