int digit1[10] = {0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d,
                  0x7d, 0x07, 0x7f, 0x6f
                 };
#define b_up 11
#define b_down 12
int cnt = 0;
int state_up = 0, state_down = 0;;
int last_state_up = 0, last_state_down = 0;
void setup() {
  pinMode(b_up, INPUT_PULLUP);
  pinMode(b_down, INPUT_PULLUP);
  for (int i = 4; i <= 10; i++) {
    pinMode(i, OUTPUT);
  }
}
void loop() {
  state_up = !digitalRead(b_up);
  state_down = !digitalRead(b_down);
  if (state_up != last_state_up) {
    if (state_up == 0) {
      cnt++;
      if (cnt >= 9) cnt = 9;
    }
    delay(40);
  }
  if (state_down != last_state_down) {
    if (state_down == 0) {
      cnt--;
      if (cnt <= 0) cnt = 0;
    }
    delay(40);
  }
  for (int i = 4; i <= 10; i++) {
    digitalWrite(i, bitRead(digit1[cnt], i - 4));
  }
  last_state_up = state_up;
  last_state_down = state_down;
}