foo.c: In function 'main':
foo.c:11:11: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   11 |  if(n%4==0&&n%100!=0||n%100==0&&n%400==0)
      |     ~~~~~~^~~~~~~~~~
foo.c:6:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    6 |   scanf("%d %d %d",&n,&y,&r);
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务