const byte segmenten[10] = {
  0b00111111,
  0b00000110,
  0b01011011,
  0b01001111,
  0b01100110,
  0b01101101,
  0b01111101,
  0b00000111,
  0b01111111,
  0b01101111
};

const int knopStart = 7;
const int knopStop = 8;

bool actief = false;
int getal = 0;

void setup() {
  DDRD |= 0b01111111;
  pinMode(knopStart, INPUT);
  pinMode(knopStop, INPUT);
  randomSeed(analogRead(A0));
}

void loop() {
  if (digitalRead(knopStart) == LOW) {
    while (digitalRead(knopStart) == LOW);
    delay(200);
    actief = true;
  }

  while (actief) {
    getal = random(10);
    PORTD = (PORTD & 0b10000000) | segmenten[getal];
    delay(1000);

    if (digitalRead(knopStop) == LOW) {
      while (digitalRead(knopStop) == LOW);
      delay(200);
      actief = false;
    }
  }

  PORTD = (PORTD & 0b10000000) | segmenten[getal];
  delay(10);
}