#define LED_PIN 4
#define BUTTON_PIN 2

void setup(){
  // Set the LED pin as output
  pinMode(LED_PIN, OUTPUT);
  // Set the button pin as input
  pinMode(BUTTON_PIN, INPUT_PULLUP);
}

void loop(){
  // Read the state of the button
  int buttonState = digitalRead(BUTTON_PIN);
  // If the button is pressed (LOW state), turn on the LED
  if (buttonState == LOW){
    digitalWrite(LED_PIN, HIGH);
  } else {
    // Otherwise, turn off the LED
    digitalWrite(LED_PIN, LOW);
  }
}