/in/foo.cc: In function 'int main()':
/in/foo.cc:7:18: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    7 |         if(y%4==0&&y%100!=0||y%400==0)
      |            ~~~~~~^~~~~~~~~~
/in/foo.cc:25:18: error: 'ac' was not declared in this scope
   25 |         return 0;ac
      |                  ^~