GivePlayerExp(playerid, ammount); //Gives the selected ID the selected ammount of experience.
GetPlayerExpLevel(playerid); //Returns the selected ID's Experience Level
GetPlayerExp(playerid); //Returns the selected ID's Experience
GetPlayerTotalExp(playerid); //Returns the selected ID's Total Experience (Experience needed to level up)

#define ExpForLevel 1000 //How much exp you need to pass a level. The Exp gets multiplied by the level. If you've got 1000 total exp then for lvl 2 it will be 2000
#define MaxLevel 99 //The maximum level a player can achieve.
#define UseProgBar // Define wheater to use the progress bar or not. Comment the line if you don't want a progress bar and leave like that if you do want a progress bar.
#define ProgBarColor 0x0000FFFF //The experience bar's color.
#define TextLabelColor 0x00FFFFFF // The textlabel's color.
#define CashForLevelUp 300 //This is the cash you get for levelling up. It gets multiplied by the level you achieved and one more time by a number you define.
#define CashMultiplier 1 //This multiplies the Cash * Level achieved by the number you want.

GivePlayerExp(playerid, exp, reason[])

#define GameTextStyle 4 //This defines the GameText's style used for the GivePlayerExp function.
#define GameTextTime 3000 //This defines the time for which the GameText for the GivePlayerExp function will be visible

public OnPlayerDeath(playerid, killerid, reason)
{
	if (killerid != playerid) {
	    if (GetPlayerExpLevel(playerid) < GetPlayerExpLevel(killerid))
	    {
    		GivePlayerExp(killerid, 100, "killing a lower level player");
	    }
	    else if (GetPlayerExpLevel(playerid) > GetPlayerExpLevel(killerid))
	    {
	    	GivePlayerExp(killerid, 300, "killing a higher level player");
	    }
	    else
	    {
	    	GivePlayerExp(killerid, 200, "killing a player at your own level");
	    }
	} // An example of using my exp system.
	return 1;
}