[LarzI]

pawn Код:

if(IsPlayerInRangeOfPoint(playerid, radius, CarPpX, CarPpY, CarPpZ))
    {
      return 1;
    }
    else
    {
        return 0;
    }

That practically does:
If the function IsPlayerInRangeOfPoint with arguments: playerid, radius, CarPpX, CarPpY and CarPpZ returns true, then return 1
Else (If the function IsPlayerInRangeOfPoint with arguments: playerid, radius, CarPpX, CarPpY and CarPpZ returns false), then return 0

So if you return the function, that will return whatever the function does (either true or false).