int ButtonState = 0;

void setup() {
  // put your setup code here, to run once:
  pinMode(2,INPUT);
  pinMode(4,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  ButtonState = digitalRead(2);

  if(ButtonState){
    digitalWrite(4,HIGH);
  }
  else{
    digitalWrite(4,LOW);
  }
}