#define LED_PIN     13
#define BUTTON_PIN  7


// the setup function runs once when you press reset or power the board
void setup() 
{
// initialize digital LED pin
pinMode(LED_PIN, OUTPUT);

// initialize digital input pin
pinMode(BUTTON_PIN, INPUT_PULLUP );

} // end setup

////////////////////////////////////////////////////////////////////////////////

// the loop function runs over and over again forever
void loop() 
{

// test if button is pressed 
if ( digitalRead( BUTTON_PIN ) == 0 )
  {
  digitalWrite(LED_PIN, HIGH );  
  } // end if
else 
  {
  digitalWrite(LED_PIN, LOW );  
  } // end else

} // end loop