const int segA = 13;
const int segB = 12;
const int segC = 14;
const int segD = 27;
const int segE = 26;
const int segF = 25;
const int segG = 33;
const int segDP = 32;

// Pre-defining the sements which light up depending on the number it wants to display.
int digits[10][7] = {{1, 1, 1, 1, 1, 1, 0}, // 0
                     {0, 1, 1, 0, 0, 0, 0}, // 1
                     {1, 1, 0, 1, 1, 0, 1}, // 2
                     {1, 1, 1, 1, 0, 0, 1}, // 3
                     {0, 1, 1, 0, 0, 1, 1}, // 4
                     {1, 0, 1, 1, 0, 1, 1}, // 5
                     {1, 0, 1, 1, 1, 1, 1}, // 6
                     {1, 1, 1, 0, 0, 0, 0}, // 7
                     {1, 1, 1, 1, 1, 1, 1}, // 8
                     {1, 1, 1, 1, 0, 1, 1}}; // 9

//Setting pins to output.
void setup() {
  pinMode(segA, OUTPUT);
  pinMode(segB, OUTPUT);
  pinMode(segC, OUTPUT);
  pinMode(segD, OUTPUT);
  pinMode(segE, OUTPUT);
  pinMode(segF, OUTPUT);
  pinMode(segG, OUTPUT);
  pinMode(segDP, OUTPUT);
}

// Checks if the number is positive or negative to display the correct symbol.
void loop() {
  int num = -123; // example number to display
  int digit = 0;

  if (num < 0) {
    digitalWrite(segG, HIGH);
    num = -num;
  }

  while (digit < 3) {
    int n = num % 10;
    int *seg = digits[n];
    digitalWrite(segA, seg[0]);
    digitalWrite(segB, seg[1]);
    digitalWrite(segC, seg[2]);
    digitalWrite(segD, seg[3]);
    digitalWrite(segE, seg[4]);
    digitalWrite(segF, seg[5]);

    if (digit == 0 && num < 100) {
      digitalWrite(segG, LOW);
    } else {
      digitalWrite(segG, seg[6]);
    }

    delay(5);

    digitalWrite(segA, LOW);
    digitalWrite(segB, LOW);
    digitalWrite(segC, LOW);
    digitalWrite(segD, LOW);
    digitalWrite(segE, LOW);
    digitalWrite(segF, LOW);
    digitalWrite(segG, LOW);

    num /= 10;
    digit++;

    if (num == 0 && digit < 3) {
      if (digit == 1 && num < 0) {
        digitalWrite(segG, HIGH);
      }
      delay(5);
    }
  } 
}