// Pin definitions for 7-segment display
const int segmentA = 2;
const int segmentB = 3;
const int segmentC = 4;
const int segmentD = 5;
const int segmentE = 6;
const int segmentF = 7;
const int segmentG = 8;

// Pin definitions for buttons
const int buttonIncrease = 9;
const int buttonDecrease = 10;

int currentNumber = 0;

void setup() {
  // Set the segment pins as outputs
  pinMode(segmentA, OUTPUT);
  pinMode(segmentB, OUTPUT);
  pinMode(segmentC, OUTPUT);
  pinMode(segmentD, OUTPUT);
  pinMode(segmentE, OUTPUT);
  pinMode(segmentF, OUTPUT);
  pinMode(segmentG, OUTPUT);
  
  // Set the button pins as inputs with pull-up resistors
  pinMode(buttonIncrease, INPUT_PULLUP);
  pinMode(buttonDecrease, INPUT_PULLUP);
  
  displayNumber(currentNumber); // Display initial number
}

void loop() {
  // Check if the increase button is pressed
  if(digitalRead(buttonIncrease) == LOW) {
    currentNumber++; // Increase the number
    if(currentNumber > 9) currentNumber = 0; // Wrap around if we exceed 9
    displayNumber(currentNumber); // Display the new number
    delay(200); // Debounce the button
  }
  
  // Check if the decrease button is pressed
  if(digitalRead(buttonDecrease) == LOW) {
    currentNumber--; // Decrease the number
    if(currentNumber < 0) currentNumber = 9; // Wrap around if we go below 0
    displayNumber(currentNumber); // Display the new number
    delay(200); // Debounce the button
  }
}

// Function to display a number on the 7-segment display
void displayNumber(int number) {
  switch(number) {
    case 0:
      digitalWrite(segmentA, HIGH);
      digitalWrite(segmentB, HIGH);
      digitalWrite(segmentC, HIGH);
      digitalWrite(segmentD, HIGH);
      digitalWrite(segmentE, HIGH);
      digitalWrite(segmentF, HIGH);
      digitalWrite(segmentG, LOW);
      break;
    case 1:
      // Define segment pins for number 1
      // (you can fill in the rest of the cases for other numbers)
      digitalWrite(segmentA, LOW);
      digitalWrite(segmentB, HIGH);
      digitalWrite(segmentC, HIGH);
      digitalWrite(segmentD, LOW);
      digitalWrite(segmentE, LOW);
      digitalWrite(segmentF, LOW);
      digitalWrite(segmentG, LOW);
      break;
    // Fill in cases for numbers 2-9
  }
}


https://www.youtube.com/watch?v=MV57rbvLSO8