int data = 12;
int latch = 11;
int clock = 9;

String digit1;
String digit2;
String digit3;
String digit4;

byte digitDp1 [10] = {B11111111,B10011111,B00100101,B00001101,B10011001,B01001001,B01000001,B00011111,B00000001,B00001001};
byte digitDp2 [10] = {B00000010,B10011110,B00100100,B00001100,B10011000,B01001000,B01000000,B00011110,B00000000,B00001000};
byte digitDp3 [10] = {B00000011,B10011111,B00100101,B00001101,B10011001,B01001001,B01000001,B00011111,B00000001,B00001001};
byte digitDp4 [10] = {B00000011,B10011111,B00100101,B00001101,B10011001,B01001001,B01000001,B00011111,B00000001,B00001001};

void setup() {
  // Serial.begin(9600);

  pinMode(data, OUTPUT);
  pinMode(latch, OUTPUT);
  pinMode(clock, OUTPUT);

  for(int i=0; i<10; i++){
    digitalWrite(latch, LOW);
    shiftOut(data,clock,LSBFIRST,digitDp3[i]);
    shiftOut(data,clock,LSBFIRST,digitDp3[i]);
    shiftOut(data,clock,LSBFIRST,digitDp3[i]);
    shiftOut(data,clock,LSBFIRST,digitDp3[i]);
    digitalWrite(latch, HIGH);
    delay(500);
  }

  delay(1000);

  // digitalWrite(latch, LOW);
  // shiftOut(data,clock,LSBFIRST,B00011111);
  // shiftOut(data,clock,LSBFIRST,B00100101);
  // digitalWrite(latch, HIGH);
}

void loop() {
  String qty = "3.20";

  int idenxDesimal = qty.indexOf('.')+1;
  String bilBulat = qty.substring(0,idenxDesimal-1);
  String desimal = qty.substring(idenxDesimal);
  

  if(bilBulat.length() == 1){
    digit1 = "0";
    digit2 = bilBulat.substring(0,1);
  }else{
    digit1 = bilBulat.substring(0,1);
    digit2 = bilBulat.substring(1,2);
  }

  if(desimal.length() == 1){
    digit3 = desimal.substring(0,1);
    digit4 = "0";
  }else{
    digit3 = desimal.substring(0,1);
    digit4 = desimal.substring(1,2);
  }

  digitalWrite(latch, LOW);
  shiftOut(data,clock,LSBFIRST,digitDp4[digit4.toInt()]);
  shiftOut(data,clock,LSBFIRST,digitDp3[digit3.toInt()]);
  shiftOut(data,clock,LSBFIRST,digitDp2[digit2.toInt()]);
  shiftOut(data,clock,LSBFIRST,digitDp1[digit1.toInt()]);
  digitalWrite(latch, HIGH);
  delay(500);

}