// Binary Counter with LEDs
int ledCount = 4;           // number of LEDs
int ledPins[] = {8, 9, 10, 11}; // LED pins (LSB to MSB)
int delayTime = 1000;       // 1 second delay

void setup() {
  // Initialize all LED pins as outputs
  for (int i = 0; i < ledCount; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
}

void loop() {
  // Count from 0 to 15
  for (int count = 0; count < 16; count++) {
    displayBinary(count);
    delay(delayTime);
  }
}

// Function to display a number in binary on LEDs
void displayBinary(int number) {
  for (int i = 0; i < ledCount; i++) {
    // Check each bit using bitwise AND
    // (1 << i) creates a bitmask for the current LED position
    // If the bit is set, turn on LED, else turn off
    digitalWrite(ledPins[i], (number & (1 << i)) ? HIGH : LOW);
  }
}