int sliderPin = A0;
//int sevenSegmentDisplayPins[8] = {0, 1, 2, 3, 4, 5, 6, 7};
int ledArray[4] = {A1, A2, A3, A4};
int switchPin = 8;
int oldSwitchValue = LOW;

int index = 0;
int sensorValue;
int outputValue;

unsigned long lastDebounceTime = 0;  // the last time the output pin was toggled
unsigned long debounceDelay = 50;    // the debounce time; increase if the output flickers

void setup() {
  // put your setup code here, to run once:
  for (int i = 0; i < 10; i++){
    pinMode(i, OUTPUT);
  }
  pinMode(A1, OUTPUT);
  pinMode(A2, OUTPUT);
  pinMode(A3, OUTPUT);
  pinMode(A4, OUTPUT);

  pinMode(switchPin, INPUT);

  for (int i = 0; i < 4; i++){
    digitalWrite(ledArray[i], HIGH);
    delay(100);
    digitalWrite(ledArray[i], LOW);
    delay(100);
    }
}

void loop() {
  // put your main code here, to run repeatedly:
  sensorValue = analogRead(sliderPin);
  outputValue = map(sensorValue, 0, 1023, 0, 9);
  displaySevenSegment(outputValue);
  int switchValue = digitalRead(switchPin);
  if (switchValue != oldSwitchValue) {
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    // whatever the reading is at, it's been there for longer than the debounce
    // delay, so take it as the actual current state:

    // if the button state has changed:
    if (switchValue != oldSwitchValue) {
      oldSwitchValue = switchValue;
      ledRoundRobin();
    }
  }
}

void ledRoundRobin() {
  digitalWrite(ledArray[index], LOW);
  if (index < 4) {
    index++;
  }
  else {
    index = 0;
  }
  digitalWrite(ledArray[index], HIGH);
}

void displaySevenSegment(int valueToDisplay){
  switch (valueToDisplay) {
    case 0:
      // 9, 7, 6, 4, 2, 1
      digitalWrite(10, LOW);
      digitalWrite(9,  HIGH);
      digitalWrite(7,  HIGH);
      digitalWrite(6,  HIGH);
      digitalWrite(5,  LOW);
      digitalWrite(4,  HIGH);
      digitalWrite(2,  HIGH);
      digitalWrite(1,  HIGH);
      break;
    case 1:
      // 6, 4
      digitalWrite(10, LOW);
      digitalWrite(9,  LOW);
      digitalWrite(7,  LOW);
      digitalWrite(6,  HIGH);
      digitalWrite(5,  LOW);
      digitalWrite(4,  HIGH);
      digitalWrite(2,  LOW);
      digitalWrite(1,  LOW);
      break;
    case 2:
      // 7, 6, 10, 1, 2
      digitalWrite(10, HIGH);
      digitalWrite(9,  LOW);
      digitalWrite(7,  HIGH);
      digitalWrite(6,  HIGH);
      digitalWrite(5,  LOW);
      digitalWrite(4,  LOW);
      digitalWrite(2,  HIGH);
      digitalWrite(1,  HIGH);
      break;
    case 3:
      // 7, 6, 10, 4, 2
      digitalWrite(10, HIGH);
      digitalWrite(9,  LOW);
      digitalWrite(7,  HIGH);
      digitalWrite(6,  HIGH);
      digitalWrite(5,  LOW);
      digitalWrite(4,  HIGH);
      digitalWrite(2,  HIGH);
      digitalWrite(1,  LOW);
      break;
    case 4:
      // 9, 6, 10, 4
      digitalWrite(10, HIGH);
      digitalWrite(9,  HIGH);
      digitalWrite(7,  LOW);
      digitalWrite(6,  HIGH);
      digitalWrite(5,  LOW);
      digitalWrite(4,  HIGH);
      digitalWrite(2,  LOW);
      digitalWrite(1,  LOW);
      break;
    case 5:
      // 7, 9, 10, 4, 2
      digitalWrite(10, HIGH);
      digitalWrite(9,  HIGH);
      digitalWrite(7,  HIGH);
      digitalWrite(6,  LOW);
      digitalWrite(5,  LOW);
      digitalWrite(4,  HIGH);
      digitalWrite(2,  HIGH);
      digitalWrite(1,  LOW);
      break;
    case 6:
      // 7, 9, 10, 1, 4, 2
      digitalWrite(10, HIGH);
      digitalWrite(9,  HIGH);
      digitalWrite(7,  HIGH);
      digitalWrite(6,  LOW);
      digitalWrite(5,  LOW);
      digitalWrite(4,  HIGH);
      digitalWrite(2,  HIGH);
      digitalWrite(1,  HIGH);
      break;
    case 7:
      // 7, 6, 4
      digitalWrite(10, LOW);
      digitalWrite(9,  LOW);
      digitalWrite(7,  HIGH);
      digitalWrite(6,  HIGH);
      digitalWrite(5,  LOW);
      digitalWrite(4,  HIGH);
      digitalWrite(2,  LOW);
      digitalWrite(1,  LOW);
      break;
    case 8:
      // 7, 6, 5, 4, 3 ,2, 1, 9, 10
      digitalWrite(10, HIGH);
      digitalWrite(9,  HIGH);
      digitalWrite(7,  HIGH);
      digitalWrite(6,  HIGH);
      digitalWrite(5,  LOW);
      digitalWrite(4,  HIGH);
      digitalWrite(2,  HIGH);
      digitalWrite(1,  HIGH);
      break;
    case 9:
      // 7, 6, 10, 9, 1
      digitalWrite(10, HIGH);
      digitalWrite(9,  HIGH);
      digitalWrite(7,  HIGH);
      digitalWrite(6,  HIGH);
      digitalWrite(5,  LOW);
      digitalWrite(4,  LOW);
      digitalWrite(2,  LOW);
      digitalWrite(1,  HIGH);
      break;
  }
}