byte segValue[10][7] = {
  {0,0,0,0,0,0,1}, 
  {1,0,0,1,1,1,1}, 
  {0,0,1,0,0,1,0}, 
  {0,0,0,0,1,1,0}, 
  {1,0,0,1,1,0,0}, 
  {0,1,0,0,1,0,0}, 
  {0,1,0,0,0,0,0},
  {0,0,0,1,1,1,1}, 
  {0,0,0,0,0,0,0}, 
  {0,0,0,0,1,0,0}  
};

byte segPin[7] = {2, 3, 4, 5, 6, 7, 8}; 
byte digitPin[3] = {11, 12, 13}; 

void setup() {
  for (int i = 0; i < 10; i++) {
    pinMode(segPin[i], OUTPUT);
  }

  for (int i = 0; i < 7; i++) {
    digitalWrite(segPin[i], 1);
  }

  for (int i = 0; i < 3; i++) {
    pinMode(digitPin[i], OUTPUT);
    digitalWrite(digitPin[i], 0);
  }
}

void loop() {
  for (int i = 0; i < 999; i++) {
    display_N(i);
    delay(100); 
  }
}

void display_N(int num) {
  int units = num % 10;
  int tens = (num / 10) % 10;
  int hundreds = (num / 100) % 10;

  segOutput(2, units);   
  segOutput(1, tens);   
  segOutput(0, hundreds); 

}

void segClear() {
  for (int i = 0; i < 7; i++) {
    digitalWrite(segPin[i], 1);
  }
}

void segOutput(int d, int Number) {
  segClear();
  digitalWrite(digitPin[d], 1);
  for (int i = 0; i < 7; i++) {
    digitalWrite(segPin[i], segValue[Number][i]);
  }
  digitalWrite(digitPin[d], 0);
  
}