nyoj-68 三点顺序

题目链接：http://acm.nyist.net/JudgeOnline/problem.php?pid=68
看的大神的解析：http://blog.csdn.net/sjl_leaf/article/details/8789785

#include<stdio.h>
#include<string.h>
int main(){
	int x1,y1,y2,x2,x3,y3;
	int sum;
	while(~scanf("%d %d %d %d %d %d",&x1,&y1,&x2,&y2,&x3,&y3)){
        if(!x1&&!x2&&!x3&&!y1&&!y2&&!y3)
            break;
		sum=(x2-x1)*(y3-y1)-(y2-y1)*(x3-x1);
		if(sum>0)
		   printf("0\n");
		else
		   printf("1\n");
	}
	return 0;
}