[Virtual1ty]

You have to use format
So it will look like this;

pawn Код:

new string[128], jmeno[MAX_PLAYER_NAME];
    GetPlayerName(playerid, jmeno, sizeof(jmeno));
    format(string, sizeof(string), "nakupy/%s.txt, jmeno);
    //write to file ... ex: new File: hFile = fopen(string, io_write);