// constants won't change. They're used here to set pin numbers:

const int buttonPin = 2; //the number of the pushbutton pin:
const int ledPin = 13;   //variable for reading the pushbutton status:
// variables will change:

int buttonState = 0;

// variable for reading the pushbutton status

void setup() {

// initialize the LED pin as on output:

pinMode(ledPin, OUTPUT);

// initialize the pushbutton pin as an input:

pinMode(buttonPin, INPUT);
}

void loop() {

// read the state of the pushbutton value:

buttonState = digitalRead(buttonPin);

// check if the pushbutton is pressed. If it is, the buttonState is HIGH:

if (buttonState, HIGH) {

digitalWrite(ledPin, HIGH);

//turn LED on:

  } 
else { //turn LED off:

digitalWrite(ledPin, LOW);

  }
}