Obstacle Detector programming code

void setup()
	{
	pinMode(13,OUTPUT);
	pinMode(3,INPUT);
	Serial.begin(9600);
	}
	void loop()
	{
	if (digitalRead(3)== LOW)
	{
	digitalWrite(13,HIGH);
	delay(10);
	}
	else
	{
	digitalWrite(13,LOW);
	delay(10);
	}
	}