You don't have to enforce a conversion from int to bool if you just want a bool. In this example you don't want to increment by 'bool', you want to increment b

You don't have to enforce a conversion from int to bool if you just want a bool. In this example you don't want to increment by 'bool', you want to increment by 1 or 0 (which are ints). So you use !!x to convert to bool and back to int. The reason I'm pointing this out is that often enough I had to work with code where this distinction was unknown to the author and you come across code like if (!!x) which is, again, just nonsense.