[Dayrion]

Use sscanf it's more easier.

PHP Code:

CMD:shift(playerid, params[])
{
    if(sscanf(params,"i", params)) return SendClientMessage(playerid, 0xFFEEFFAA, "USAGE: /form [1-3]");

    switch (params[0])
    {
        case '1':
        {
            SetPlayerTeam(playerid, Homid);
            GameTextForPlayer(playerid, "~W~Form: ~G~Homid", 5000, 6);
        }
        case '2':
        {
            SetPlayerTeam(playerid, Crinos);
            GameTextForPlayer(playerid, "~W~Form: ~G~Crinos", 5000, 6);
        }
        case '3':
        {
            SetPlayerTeam(playerid, Lupus);
            GameTextForPlayer(playerid, "~W~Form: ~G~Lupus", 5000, 6);
        }
    }
    // If you have more than 9 options, use strval:
    /*
    new choice = strval(params[0]);
    if (choice == 1)
    else if (choice == 2)
    // etc
    */
    if (GetPlayerTeam(playerid) == Homid)
    {
        SendClientMessage(playerid, -1, "You've shifted into the form homid(human)");
        SetPlayerHealth(playerid, 150);
        SetPlayerArmour(playerid, 50);
        //werewolf_speed required
    }
    return 1;
} 


If you don't want, define isnull().

PHP Code:

#if !defined isnull
    #define isnull(%1) ((!(%1[0])) || (((%1[0]) == '\1') && (!(%1[1]))))
#endif