foo.cc: In function ‘int main()’:
foo.cc:8:18: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
    8 |         if(y%4==0&&y%100!=0||y%400==0)
      |            ~~~~~~^~~~~~~~~~
foo.cc:20:26: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
   20 |                 if(y%4==0&&y%100!=0||y%400==0)
      |                    ~~~~~~^~~~~~~~~~