解釋
不要往下滑
#include <stdio.h>
int main(){
int x1,y1,x2,y2;
while(scanf("%d%d%d%d",&x1,&y1,&x2,&y2)==4){
if(!x1&&!y1&&!x2&&!y2) break;
if(x1==x2&&y1==y2) printf("0\n");
else if(x1==x2||y1==y2||(x1+y1==x2+y2)||(x1-y1==x2-y2)) printf("1\n");
else printf("2\n");
}
}