int ledPin = 13;     // LED connected to digital pin 13
int buttonPin = 2;   // Button connected to digital pin 2
int buttonState = 0; // Variable to store button state

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP); 
  // INPUT_PULLUP uses internal resistor; button reads LOW when pressed
}

void loop() {
  buttonState = digitalRead(buttonPin);

  if (buttonState == LOW) {      // Button pressed
    digitalWrite(ledPin, HIGH);  // Turn LED ON
  } else {
    digitalWrite(ledPin, LOW);   // Turn LED OFF
  }
}