#define BUTTONPIN 2
#define LEDPIN 13
void setup() {

  Serial.begin(9600);
 pinMode(BUTTONPIN,INPUT);
pinMode(LEDPIN, OUTPUT);
}

void loop() {
  String pf;
  pf = "Button?: ";
  byte SchalterZustand;
  SchalterZustand = (digitalRead(BUTTONPIN));

  Serial.println(pf);
  Serial.println(SchalterZustand,DEC);

if (SchalterZustand == 1)
{ 
digitalWrite(LEDPIN, HIGH);
}
if (SchalterZustand == 0)
{
  digitalWrite(LEDPIN, LOW);
}
  // put your main code here, to run repeatedly:

}