const int segmentPins[7] = {2, 3, 4, 5, 6, 7, 8}; 
const int digitPins[3] = {9, 10, 11}; 

const byte digits[10] = {
  0b00111111, // 0
  0b00000110, // 1
  0b01011011, // 2
  0b01001111, // 3
  0b01100110, // 4
  0b01101101, // 5
  0b01111101, // 6
  0b00000111, // 7
  0b01111111, // 8
  0b01101111  // 9
};

int number = 0; 

void setup() {
  for (int i = 0; i < 7; i++) {
    pinMode(segmentPins[i], OUTPUT);
  }

  for (int i = 0; i < 3; i++) {
    pinMode(digitPins[i], OUTPUT);
    digitalWrite(digitPins[i], HIGH); 
  }
}

void loop() {
  displayNumber(number);

  static unsigned long lastUpdate = 0;
  if (millis() - lastUpdate >= 200) {  
    lastUpdate = millis();
    number = (number + 1) % 1000;
  }
}

void displayNumber(int number) {
  int hundreds = number / 100;       
  int tens = (number / 10) % 10;     
  int ones = number % 10;            

  displayDigit(hundreds, 0);  
  delay(5);
  displayDigit(tens, 1);      
  delay(5);
  displayDigit(ones, 2);      
  delay(5);
}

void displayDigit(int num, int digitIndex) {
  for (int i = 0; i < 3; i++) {
    digitalWrite(digitPins[i], HIGH);
  }

  byte segments = digits[num];
  for (int i = 0; i < 7; i++) {
    digitalWrite(segmentPins[i], segments & (1 << i));
  }

  digitalWrite(digitPins[digitIndex], LOW);
}