foo.cc: In function 'int printMonth(int, int)':
foo.cc:47:1: warning: no return statement in function returning non-void [-Wreturn-type]
 } 
 ^
foo.cc: In function 'int main()':
foo.cc:96:11: warning: unused variable 'month' [-Wunused-variable]
  int year,month,d;
           ^~~~~
foo.cc:96:17: warning: unused variable 'd' [-Wunused-variable]
  int year,month,d;
                 ^

[Hydro](https://hydro.ac)提供评测服务