foo.cc: In function 'int main()':
foo.cc:9:28: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    9 |   if(year%400==0||year%4==0&&year%100!=0)
      |                   ~~~~~~~~~^~~~~~~~~~~~~
foo.cc:15:23: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   15 |  { if(mon<=7&&mon%2==0&&mon!=2||mon>=8&&mon%2==1)
      |       ~~~~~~~~~~~~~~~~^~~~~~~~

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