#define PIN_LED 3
#define BUTTON 6
bool knop;
bool statusled;

void setup() {
  pinMode(PIN_LED, OUTPUT);
  pinMode(BUTTON, INPUT);
}

void loop() {
  knop = digitalRead(BUTTON);
  if (knop == HIGH) {
    statusled = digitalRead(PIN_LED);
    digitalWrite(PIN_LED, !statusled);
  }
}