new Combustivel[MAX_VEHICLES];

if(!strcmp(cmd, "/abastecer", true)) {
   if(!IsPlayerInAnyVehicle(playerid)) return SendClientMessage(playerid, -1, "Não está em um carro.");
   tmp = strtok(cmdtext, idx);
   if(!strlen(tmp)) return SendClientMessage(playerid, -1, "/abastecer [qtd].");
   new qtd = strval(tmp);
   Combustivel[GetPlayerVehicleID(playerid)] += qtd;
   new string[50];
   format(string, 50, "Combustivel do carro: %d", Combustivel[GetPlayerVehicleID(playerid)]);
   SendClientMessage(playerid, -1, string);
   return 1;
}