View Code of Problem 67

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