int unidad=0;
int decena=0;
int centena=0;
int millar=0;
int x=0;

const int decoder[]={63,6,91,79,102,109,125,7,127,111};
const int espe[]={121,115,109,121};
const int buttonUpPin = A0;
const int buttonDownPin = A1;
bool lastButtonUpState = HIGH;
bool lastButtonDownState = HIGH;


void display7(int valor)
{
  for (x=0; x<7; x++){
    digitalWrite((x+2), bitRead(valor, x));
  }
}



void conmutar1(){
  for (x = 0; x < 5; x++) {
    // Display 1: Units
    digitalWrite(12, LOW);
    digitalWrite(11, HIGH);
    digitalWrite(10, HIGH);
    digitalWrite(9, HIGH);
    display7(espe[unidad]);
    delay(200);

    // Display 2: Tens
    digitalWrite(12, HIGH);
    digitalWrite(11, LOW);
    digitalWrite(10, HIGH);
    digitalWrite(9, HIGH);
    display7(espe[decena]);
    delay(200);

    // Display 3: Hundreds
    digitalWrite(12, HIGH);
    digitalWrite(11, HIGH);
    digitalWrite(10, LOW);
    digitalWrite(9, HIGH);
    display7(espe[centena]);
    delay(200);

    // Display 4: Thousands
    digitalWrite(12, HIGH);
    digitalWrite(11, HIGH);
    digitalWrite(10, HIGH);
    digitalWrite(9, LOW);
    display7(espe[millar]);
    delay(200);
  }
}

void conmutar2() {
  for (x = 0; x < 5; x++) {
    // Display 1: Units
    digitalWrite(12, HIGH);
    digitalWrite(11, HIGH);
    digitalWrite(10, HIGH);
    digitalWrite(9, LOW);
    display7(decoder[unidad]);
    delay(200);

    // Display 2: Tens
    digitalWrite(12, HIGH);
    digitalWrite(11, HIGH);
    digitalWrite(10, LOW);
    digitalWrite(9, HIGH);
    display7(decoder[decena]);
    delay(200);

    // Display 3: Hundreds
    digitalWrite(12, HIGH);
    digitalWrite(11, LOW);
    digitalWrite(10, HIGH);
    digitalWrite(9, HIGH);
    display7(decoder[centena]);
    delay(200);

    // Display 4: Thousands
    digitalWrite(12, LOW);
    digitalWrite(11, HIGH);
    digitalWrite(10, HIGH);
    digitalWrite(9, HIGH);
    display7(decoder[millar]);
    delay(200);
}

  return;
}

void setup() {
  int pin;
  for (pin=2; pin<=12; pin++) {
    pinMode(pin, OUTPUT);
  }
  pinMode(buttonUpPin, INPUT_PULLUP);
  pinMode(buttonDownPin, INPUT_PULLUP);
}

void loop() {
  bool buttonUpState = digitalRead(buttonUpPin);
  bool buttonDownState = digitalRead(buttonDownPin);

  if (buttonUpState == LOW && lastButtonUpState == HIGH) {
    for(millar=0; millar<=9; millar++)
      for(centena=0; centena<=9; centena++)
        for(decena=0; decena<=9; decena++)
          for(unidad=0; unidad<=9; unidad++)
            conmutar2();
  } else if (buttonDownState == LOW && lastButtonDownState == HIGH) {
    for(millar=9; millar>=0; millar--)
      for(centena=9; centena>=0; centena--)
        for(decena=9; decena>=0; decena--)
          for(unidad=9; unidad>=0; unidad--)
            conmutar2();

  }else{
    for(unidad=0; unidad<1; unidad++)
     for(decena=2; decena<3; decena++)
      for(centena=1; centena<2; centena++)
        for(millar=0; millar<1; millar++)
          conmutar1();
  }}