public OnPlayerKeyStateChange(playerid, newkeys, oldkeys)
{
    if(PRESSED(KEY_FIRE))
    {
        if(GetPlayerWeapon(playerid) == 4)
        {
            new
                Float:X,
                Float:Y,
                Float:Z;
            GetPlayerPos(playerid, X, Y, Z);
            foreach(Player, i)
            {
                if ( gTeam [ playerid ] != gTeam [ i ] )
                {
                    if(IsPlayerInRangeOfPoint(playerid, 0.5, X, Y, Z))
                    {
                        Infected(i);
                        new Float:NewHP;
                        GetPlayerArmour(playerid,NewHP);
                        if(NewHP < OldHP[playerid])
                        {
                            Arena[ZombiesKills] ++;
                            switch(Arena[ZombiesKills])
                            {
                                case 5: GameTextForAll("~r~HUMAN SCORE: 5",4000,4);
                                case 10: GameTextForAll("~r~HUMAN SCORE: 10",4000,4);
                                case 15: GameTextForAll("~r~HUMAN SCORE: 15",4000,4);
                                case 20: GameTextForAll("~r~HUMAN SCORE: 20",4000,4);
                                case 25: GameTextForAll("~r~HUMAN SCORE: 25",4000,4);
                                case 30: GameTextForAll("~r~HUMAN SCORE: 30",4000,4);
                                case 35: GameTextForAll("~r~HUMAN SCORE: 35",4000,4);
                                case 40: GameTextForAll("~r~HUMAN SCORE: 40",4000,4);
                                case 45: GameTextForAll("~r~HUMAN SCORE: 45",4000,4);
                                case 50:
                                {
                                    GameTextForAll("~r~HUMAN SCORE: 50 ~n~~w~CHANGING MAP",4000,4);
                                    AnnounceWinner();
                                }
                            }
                        }
                    }
                }
            }
        }
    }
    return 1;
}

public Infected(playerid)
{
    new
        name    [ MAX_PLAYER_NAME ],     //Added strings to the top.
        string4 [ 52 + MAX_PLAYER_NAME ] //Fixed string size.
    ;

    //Fixed how the script looked.
    ResetPlayerWeapons      ( playerid);
    SetPlayerColor          ( playerid,Z_COLOR);
    SetPlayerTeam           ( playerid,TEAM_ZOMBIE);
    SetPlayerHealth         ( playerid,50);
    SetPlayerWeather        ( playerid,32);
    SetPlayerTime           ( playerid,24,0);
    GetPlayerName           ( playerid, name, sizeof(name));
    format                  ( string4, sizeof(string4), "Player %s has just been infected turned into [Zombie]",name);
    SendClientMessageToAll  ( COLOR_RED,string4);
    GameTextForPlayer       ( playerid,"~r~ YOU JUST BEEN ZOMBIFIED INTO INFECTED SIDE",6000,4);
    GivePlayerWeapon        ( playerid,KNIFE,100);
    SetPlayerSkin           ( playerid,162);
    gTeam [ playerid ] = TEAM_ZOMBIE; //Added this line.
    return 1;
}