foo.cc: In function 'int IsLeapYear(int)':
foo.cc:17:22: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   17 |  return ((year%4==0) && (year%100!=0)||year%400==0);
      |          ~~~~~~~~~~~~^~~~~~~~~~~~~~~~
foo.cc: In function 'int DateDiff(tagDate, tagDate)':
foo.cc:58:10: warning: unused variable 'date3' [-Wunused-variable]
   58 |  tagDate date3;
      |          ^~~~~

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