int Button = 9;
int LED_PIN = 4;
int buttonState = 0;

void setup()
{
  pinMode(Button, INPUT);
  pinMode(LED_PIN, OUTPUT);
}

void loop()
{
  // read the state of the pushbutton value
  buttonState = digitalRead(Button);
  // check if pushbutton is pressed.  if it is, the
  // buttonState is HIGH
  if (buttonState == HIGH) {
    // turn LED on
    digitalWrite(LED_PIN, HIGH);
  } else {
    // turn LED off
    digitalWrite(LED_PIN, LOW);
  }
  delay(10); // Delay a little bit to improve simulation performance
}