const int clockPin = 4;
const int latchPin = 3;
const int dataPin = 2;

uint16_t cislo = 0;
unsigned long previousMillis = 0;
const int cifry[]= {
0b00000011,//0
0b10011111,//1
0b00100101,//2
0b00001101,//3
0b10011001,//4
0b01001001,//5
0b01000001,//6
0b00011111, //7
0b00000001,//8
0b00001001,//9
0b11111111, //-

};
uint8_t segment[] = {1, 2, 4, 8,};
void setup() {
  // put your setup code here, to run once:
    pinMode(latchPin, OUTPUT);
    pinMode(dataPin, OUTPUT);
    pinMode(clockPin, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
    
    unsigned long currentMillis= millis();
    if(currentMillis - previousMillis >=300){
      previousMillis=currentMillis;

    cislo = (cislo + 1)%10000;
    }
    zobrazCislo(cislo);
}
void zobrazCislo(int cislo)
{
  for(int i=0; i<4; i++)
  {
    uint8_t cifra = cislo%10;
    cislo /= 10;
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin,clockPin,LSBFIRST,cifry[cifra]);
  shiftOut(dataPin,clockPin,MSBFIRST,segment[i]);
  digitalWrite(latchPin, HIGH);
  }

}