byte leftPin[] = {2, 4, 5, 18, 19, 22, 23};   // Pins for left seven-segment display
byte rightPin[] = {13, 12, 14, 27, 26, 25, 33};   // Pins for right seven-segment display

const byte count[10] = { 
  //GFEDCBA
  B01000000,  //0
  B01111001,  //1
  B00100100,  //2
  B00110000,  //3
  B00011001,  //4
  B00010010,  //5
  B00000011,  //6
  B01111000,  //7
  B00000000,  //8
  B00011000   //9
};

void setup() {
  for (int i = 0; i < 7; i++) {
    pinMode(leftPin[i], OUTPUT);
    pinMode(rightPin[i], OUTPUT);
  }
}

void loop() {
  for (int i = 0; i < 100; i++) { 
    byte leftDigit = i / 10;
    byte rightDigit = i % 10;
    SevenSeg(count[leftDigit], count[rightDigit]);
    delay(1000);
  }
}

void SevenSeg(byte leftBit, byte rightBit) { 
  for (int i = 0; i < 7; i++) {
    digitalWrite(leftPin[i], bitRead(leftBit, i));
    digitalWrite(rightPin[i], bitRead(rightBit, i));
  }
}