// Pin definitions
const int buttonPin = 2;    // Push button pin (using internal pull-up)
const int ledPins[] = {3, 4, 5}; // LED pins (3 LEDs)
const int numLeds = 3;       // Number of LEDs

// Variables
int counter = 0;            // Tracks button presses
int lastButtonState = HIGH; // For button debouncing
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;

void setup() {
  // Set up LEDs as outputs
  for (int i = 0; i < numLeds; i++) {
    pinMode(ledPins[i], OUTPUT);
    digitalWrite(ledPins[i], LOW);
  }
  
  // Set up button with internal pull-up resistor
  pinMode(buttonPin, INPUT_PULLUP);
}

void loop() {
  int reading = digitalRead(buttonPin);
  
  // Debounce logic
  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }
  
  if ((millis() - lastDebounceTime) > debounceDelay) {
    // If the button state has changed:
    if (reading == LOW && lastButtonState == HIGH) {
      // Button pressed (LOW because of pull-up)
      counter++;
      
      // Reset counter if exceeds number of LEDs
      if (counter > numLeds) {
        counter = 0;
      }
      
      // Update LEDs based on counter
      updateLeds();
    }
  }
  
  lastButtonState = reading;
}

void updateLeds() {
  // Turn off all LEDs first
  for (int i = 0; i < numLeds; i++) {
    digitalWrite(ledPins[i], LOW);
  }
  
  // Turn on LEDs up to the current counter value
  for (int i = 0; i < counter; i++) {
    digitalWrite(ledPins[i], HIGH);
  }
}