[Jefff]

pawn Код:

stock bool:IsValidCaracter(nick[])
{
    new d;
    while(nick[d] != EOS)
    {
        if(!('0' <= nick[d] <= '9') || !('A' <= nick[d] <= 'Z') || !('a' <= nick[d] <= 'z'))
            if((nick[d] != '$') && (nick[d] != '_') && (nick[d] != '@') && (nick[d] != '=')) return true;
        d++;
    }
    return false;
}

if(IsValidCaracter(nick[])) return wrong letters in nick