I am working on room reservation system and having some problem...
I am trying to fix something that's wrong with the code..but doesn't seems to get it.
I am trying let the users select the rooms (any two reservation cannot book the same room)
You seem to have quite a bit of code duplication that needs to be reduced. Using more functions would probably be advantageous to help reduce this duplication, and should also reduce the size of main() which is way too long (just shy of 3000 lines). Try to keep your functions small and try to have them do one thing very well (at most 50 lines).
You also seem to be using goto, you really should be using one of the other more acceptable loop types, ie., while(), do/while(), for(;;) instead.
Why is your structure defined within that function. Normally structures and classes are defined in the global scope so all the functions can see the function.