int buttonState = 0;
void setup()
{
  pinMode(2, INPUT);
  pinMode(LED_BUILTIN, OUTPUT);
}
void loop()
{
  value
  buttonState = digitalRead(2);
  if it is, the
  if (buttonState == HIGH) {
    digitalWrite(LED_BUILTIN, HIGH);
  } else {
    digitalWrite(LED_BUILTIN, LOW);
  }  delay(10); 
}