I hope you understand what we are doing and not just copy pasting tho
Now, You read the file correctly, you wan't to check if a player pushed a button from your array right ?
You can't use g_iButtons[ButtonIDs], because ButtonIDs is just a counter ( You should change its name tho ), so if ButtonIDs == 3, You would just be getting iButtons[3], but in our example it would cause an index out of bounds error anyway.
So what you need to use is loop through all g_iButtons and check if any of them match.