const int LEDPIN = 13;
const int BUTTONPIN = 7;

void setup() {
  // put your setup code here, to run once:
  pinMode(LEDPIN, OUTPUT);
  pinMode(BUTTONPIN, INPUT_PULLUP);
}

void loop() {
  // put your main code here, to run repeatedly:
  int digitalval = digitalRead(BUTTONPIN);

  if(HIGH == digitalval)
  {
    digitalWrite(LEDPIN, LOW);//turn off
  }
  else
  {
    digitalWrite(LEDPIN, HIGH);//turn on
  }
}