const int segA = 2;
const int segB = 3;
const int segC = 4;
const int segD = 5;
const int segE = 6;
const int segF = 7;
const int segG = 8;

const int buttonUp = 10;
const int buttonDown = 11;

int counter = 0;

const byte digit[10] = {
  0b00111111, 
  0b00000110, 
  0b01011011, 
  0b01001111, 
  0b01100110, 
  0b01101101, 
  0b01111101, 
  0b00000111, 
  0b01111111, 
  0b01101111  
};

void setup() 
{
  pinMode(segA, OUTPUT);
  pinMode(segB, OUTPUT);
  pinMode(segC, OUTPUT);
  pinMode(segD, OUTPUT);
  pinMode(segE, OUTPUT);
  pinMode(segF, OUTPUT);
  pinMode(segG, OUTPUT);
  pinMode(buttonUp, INPUT_PULLUP);
  pinMode(buttonDown, INPUT_PULLUP);
}

void loop() {
  
  bool upState = digitalRead(buttonUp);
  bool downState = digitalRead(buttonDown);
  if (upState == LOW) {
    counter++;
    if (counter > 9) counter = 0; 
    displayDigit(counter);
    delay(300); 
  }

  if (downState == LOW) {
    counter--;
    if (counter < 0) counter = 9; 
    displayDigit(counter);
    delay(300); 
  }
}

void displayDigit(int num) {
  digitalWrite(segA, digit[num] & 0b00000001);
  digitalWrite(segB, digit[num] & 0b00000010);
  digitalWrite(segC, digit[num] & 0b00000100);
  digitalWrite(segD, digit[num] & 0b00001000);
  digitalWrite(segE, digit[num] & 0b00010000);
  digitalWrite(segF, digit[num] & 0b00100000);
  digitalWrite(segG, digit[num] & 0b01000000);
}