SendClientMessage(playerid, -1, "{FF0000}Hello!, {FFFFFF}I'm Danny! :)");

{FF0000} = Red
{FFFFFF} = White

stock Kills[MAX_PLAYERS char];
#define Kills[%0] Kills{%0}

//OnPlayerDeath
    if(killerid != INVALID_PLAYER_ID) {
        if(++Kills[killerid] == 20) {
            GameModeExit();
            return true;
        }
    }

//OnGameModeInit
SetTimer("AreaCheck", 20 * 1000, true);

forward AreaCheck();
public AreaCheck()
{
    for(new i, Float: health; i != MAX_PLAYERS; ++i) { //foreach if available
        if(IsPlayerInRangeOfPoint(i, RADIUS, X, Y, Z)) { //insert radius and coords
        //Checks if the player in in that circle
        //You could use other function to
        //Like IsPlayerInArea (checks if the player is in an axial sqaure)
        //Or IsPlayerInPerimeter, checks if the player is in a perimeter
            GetPlayerhealth(i, health);
            SetPlayerHealth(i, health - 10);
        }
    }
}

// Credit below to TiMxD of SA-MP Forums and RaGEZONE Forums

	if(strcmp(cmd, "/ooc", true) == 0 || strcmp(cmd, "/o", true) == 0)
	{
	    if(IsPlayerConnected(playerid))
	    {
	        if(pInfo[playerid][pLogged] != 1)
	        {
	            SendClientMessage(playerid, COLOR_GREY, "* You havent Logged in yet!");
	            return 1;
	        }
			GetPlayerName(playerid, pName, sizeof(pName));
			new length = strlen(cmdtext);
			while ((idx < length) && (cmdtext[idx] <= ' '))
			{
				idx++;
			}
			new offset = idx;
			new result[64];
			while ((idx < length) && ((idx - offset) < (sizeof(result) - 1)))
			{
				result[idx - offset] = cmdtext[idx];
				idx++;
			}
			result[idx - offset] = EOS;
			if(!strlen(result))
			{
				SendClientMessage(playerid, COLOR_GREY, "USAGE: /ooc [text]");
				return 1;
			}
			if(OOC == 1)
			{
				format(string, sizeof(string), "(( %s: %s ))", pName, result);
				SendClientMessageToAll(COLOR_WHITE,string);
				format(string, sizeof(string), "[OOC] %s: %s",pName,result);
				SaveOOC(string);
			}
			else
			{
			    if(pAdmin[playerid] == 0)
			    {
					SendClientMessage(playerid,COLOR_GREY,"* The OOC channel has been disabled!");
				}
			}
		}
		return 1;
	}

	if(strcmp(cmd, "/b", true) == 0)
	{
	    if(IsPlayerConnected(playerid))
	    {
	        if(pInfo[playerid][pLogged] != 1)
	        {
	            SendClientMessage(playerid, COLOR_GREY, "* You havent logged in yet!");
	            return 1;
	        }
			GetPlayerName(playerid, pName, sizeof(pName));
			new length = strlen(cmdtext);
			while ((idx < length) && (cmdtext[idx] <= ' '))
			{
				idx++;
			}
			new offset = idx;
			new result[64];
			while ((idx < length) && ((idx - offset) < (sizeof(result) - 1)))
			{
				result[idx - offset] = cmdtext[idx];
				idx++;
			}
			result[idx - offset] = EOS;
			if(!strlen(result))
			{
				SendClientMessage(playerid, COLOR_GREY, "USAGE: /b [Local OOC Chat]");
				return 1;
			}
			format(string, sizeof(string), "(( %s: %s ))", pName, result);
			ProxDetector(12.0, playerid, string,COLOR_CHAT4,COLOR_CHAT4,COLOR_CHAT4,COLOR_CHAT4,COLOR_CHAT4);
			printf("%s", string);
		}
		return 1;
	}

// Credit above to TiMxD of SA-MP Forums and RaGEZONE Forums

#define COLOR_WHITE     0xFFFFFFFF
#define COLOR_YELLOW    0xFFFF00AA
#define COLOR_ORANGE    0xF6970CAA
#defome COLOR_GREY      0xCECECEFF
#define COLOR_ME        0xB360FDFF

CMD:report(playerid, params[])
{
    new id, message[112];
    if(sscanf(params, "us[112]", id, message))
        return SendClientMessage(playerid, COLOR_YELLOW, "SYNTAX: /report [nick/id] [message]");
    if(id == INVALID_PLAYER_ID)
        return SendClientMessage(playerid, COLOR_WHITE, "ERROR: You specified an invalid player ID.");

    new string[128];
    if(strlen(message) > 40)
    {
        format(string, sizeof(string), "REPORT: Sent by %s(%d) against %s(%d).", GetName(playerid), playerid, GetName(id), id);
        // I don't know what your function is for sending messages to admins, that would go here (send "string" as the message).
        format(string, sizeof(string), "REPORT MESSAGE: %s", message);
        // I don't know what your function is for sending messages to admins, that would go here (send "string" as the message).
    }
    else
    {
        format(string, sizeof(string), "REPORT: Sent by %s(%d) against %s(%d). Message: %s", GetName(playerid), playerid, GetName(id), id, message);
        // I don't know what your function is for sending messages to admins, that would go here (send "string" as the message).
    }
    return 1;
}

CMD:whisper(playerid, params[])
{
    new id, message[41];
    if(sscanf(params, "us[41]", id, message))
        return SendClientMessage(playerid, COLOR_YELLOW, "SYNTAX: /report [nick/id] [message]");
    if(id == INVALID_PLAYER_ID)
        return SendClientMessage(playerid, COLOR_WHITE, "ERROR: You specified an invalid player ID.");
    if(strlen(message) > 41)
        return SendClientMessage(playerid, COLOR_WHITE, "ERROR: Your message cannot be longer than 41 characters.");
        
    new string[128];
    format(string, sizeof(string), "Whisper| %s says; %s", GetName(playerid), message);
    SendClientMessage(id, COLOR_WHITE, string);
    format(string, sizeof(string), "Whisper| %s sent to %s", message, GetName(id));
    SendClientMessage(playerid, COLOR_WHITE, string);
    return 1;
}

CMD:me(playerid, params[])
{
    if(isnull(params))
        return SendClientMessage(playerid, COLOR_YELLOW, "SYNTAX: /me [action]");

    new string[128];
    format(string, sizeof(string), "* %s %s", GetName(playerid), params);
    SendNearbyMessage(playerid, COLOR_ME, string);
    return 1;
}

CMD:do(playerid, params[])
{
    if(isnull(params))
        return SendClientMessage(playerid, COLOR_YELLOW, "SYNTAX: /do [enviornment]");

    new string[128];
    format(string, sizeof(string), "%s (( %s ))", params, GetName(playerid));
    SendNearbyMessage(playerid, COLOR_ME, string);
    return 1;
}

CMD:ooc(playerid, params[])
{
    if(isnull(params))
        return SendClientMessage(playerid, COLOR_YELLOW, "SYNTAX: /(o)oc [message]");
    if(strlen(params) > 91)
        return SendClientMessage(playerid, COLOR_WHITE, "ERROR: Your message cannot be longer than 91 characters.");

    new string[128];
    format(string, sizeof(string), "OOC| %s(%d): %s", GetName(playerid), playerid, params);
    SendClientMessageToAll(COLOR_ORANGE, string);
    return 1;
}

CMD:b(playerid, params[])
{
    if(isnull(params))
        return SendClientMessage(playerid, COLOR_YELLOW, "SYNTAX: /b [message]");
    if(strlen(params) > 90)
        return SendClientMessage(playerid, COLOR_WHITE, "ERROR: Your message cannot be longer than 90 characters.");

    new string[128];
    format(string, sizeof(string), "(( %s(%d): %s ))", GetName(playerid), playerid, params);
    SendNearbyMessage(playerid, COLOR_GREY, string);
    return 1;
}

stock SendNearbyMessage(playerid, color, string[])
{
    new Float:Pos[3];
    GetPlayerPos(playerid, Pos[0], Pos[1], Pos[2]);
    foreach(Player, i)
    {
        if(IsPlayerInRangeOfPoint(i, 20, Pos[0], Pos[1], Pos[2]))
            SendClientMessage(i, color, string);
    }
}

CMD:time(playerid, params[])
{
    if (isnull(params)) return SendClientMessage(playerid, -1, "{C0C0C0}Usage: /time <time id>");
    return SetPlayerTime(playerid, strval(params));
}

 error 017: undefined symbol "isnull"
warning 202: number of arguments does not match definition

1 Error.