foo.cc: In function 'int IsLeapYear(int)':
foo.cc:9:30: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(year%400==0 || year%4==0 && year%100!=0)
                    ~~~~~~~~~~^~~~~~~~~~~~~~
foo.cc: In function 'int DaysOfMonth(int, int)':
foo.cc:33:6: warning: variable 'day' set but not used [-Wunused-but-set-variable]
  int day;
      ^~~
foo.cc:46:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^

[Hydro](https://hydro.ac)提供评测服务