int buttonState = 0;

void setup() 
{
  pinMode(2, INPUT);      // Set button as input
  pinMode(13, OUTPUT);        // Set LED as output
}

void loop() 
{
  //read the state of the push button
  buttonState = digitalRead(2);
  //check if push button is pushed.
  //if button state is HIGH
  if (buttonState == HIGH) 
  {
    // Button pressed: Blink the LED
    digitalWrite(13, HIGH);
  } 
  else 
  {
    // Button not pressed: LED off
    digitalWrite(13, LOW);
  }
  delay(10);
}