foo.cc: In function 'int isLeapYear(int)':
foo.cc:5:14: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    5 |  if(year%4==0&&year%100!=0||year%400==0)
      |     ~~~~~~~~~^~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:57:35: error: 'month' was not declared in this scope
   57 |   first=weekdayOfTheFirstDay(year,month);
      |                                   ^~~~~

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