[AndreT]

This might be confusing for a beginner, but I have a solution for such commands/parts of script using only one native function.

pawn Код:

if(!strcmp(cmd, "/fixveh", true))
{
    new vID = GetPlayerVehicleID(playerid);
    if(vID != 0)
    {
        RepairVehicle(vID);
    }
    return 1;
}

What's the benefit from this? You might start arguing me over the necessity of such "optimization", but theoretically speaking this is faster than a command that first calls IsPlayerInAnyVehicle and then GetPlayerVehicleID. And further on, if you're going to do more things with the vehicle ID, you're going to need to store it in a variable anyways (or it would be good to do so).

GetPlayerVehicleID(playerid) returns 0 when the player isn't in a vehicle, so this is an helpful thing to keep in mind.