/in/foo.cc: In function 'bool op(int)':
/in/foo.cc:32:2: error: 'a' was not declared in this scope
  a=num%10;
  ^
/in/foo.cc:33:2: error: 'b' was not declared in this scope
  b=((num-a)/10)%10;
  ^
/in/foo.cc:39:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^