It is a recursive function. The first character entered is printed last. So you have a stack model.
To expand on vlad's answer (because I started typing it ages ago and didn't finish ;) ):
It's recursive - i.e. baklanges calls itself.
It only outputs a letter after the recursive call returns - i.e. after recursion ends.
The first time cout << c
executes will be within the deepest recursive call - i.e. it will be the last letter entered.
The next time it executes will be in the second deepest recursion, i.e. the second last character entered.
And so on...