foo.cc: In member function 'bool num::check(int)':
foo.cc:41:20: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
   41 |         if(val>>w&1!=0)return true;
      |                   ~^~~
foo.cc: In member function 'bool num::change(int)':
foo.cc:46:5: warning: no return statement in function returning non-void [-Wreturn-type]
   46 |     }
      |     ^
foo.cc: In member function 'int num::get()':
foo.cc:51:5: warning: control reaches end of non-void function [-Wreturn-type]
   51 |     }
      |     ^

[Hydro](https://hydro.ac)提供评测服务