foo.cc: In function 'int isLeapYear(int)':
foo.cc:7:23: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    7 |  return year % 4 == 0 && year % 100 != 0 || year % 400 == 0;
      |         ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:49:19: warning: unused variable 'j' [-Wunused-variable]
   49 |  int year, month, j = 0;
      |                   ^

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