An empty string is basically just nothing. A quote and then an end quote. In wc3edit.net, looks like this.
Code:
If Player 1 chooses the name "Dick" (aka the 4th available player name) then you set PlayerNameArray(3) to empty string (aka nothing)
This is because arrays start at 0. So:
PlayerNameArray(0) = "John"
PlayerNameArray(1) = "Tim"
PlayerNameArray(2) = "Mark"
PlayerNameArray(3) = "Dick"
PlayerNameArray(4) = "Harry"
Now in your procedure for choosing names put the condition:
If the name being chosen by the user is equal to an empty string, then ask the user to re-choose.
Empty String on wikipedia:
http://en.wikipedia.org/wiki/Empty_stri ... _Languages