foo.cc: In function ‘int main()’:
foo.cc:8:21: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
    8 |            if(y%4==0&&y%100!=0||y%400==0)
      |               ~~~~~~^~~~~~~~~~
foo.cc:7:11: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wdangling-else]
    7 |         if(m==2)
      |           ^