Error with const

Hello here,
I got a problem with XCode :


I use const on .h but i say me i got a problem and don’t understand it. My function in the .h is under private :
I have no problem with other method.
Some one understand ?

you can’t have const at the end of a non-member function. In other words it has to belong to a class.

bool FBullCowGame::IsIsogram(FString Guess) const

Thank you very much.
I forgot the class name before it’s such not nice mistake.