int pinA = 2, pinB = 3, pinC = 4, pinD = 5, pinE = 6, pinF = 7, pinG = 8;  
int D1 = 10, D2 = 11, D3 = 12;

void setup() {
  pinMode(pinA, OUTPUT);
  pinMode(pinB, OUTPUT);
  pinMode(pinC, OUTPUT);
  pinMode(pinD, OUTPUT);
  pinMode(pinE, OUTPUT);
  pinMode(pinF, OUTPUT);
  pinMode(pinG, OUTPUT);
  pinMode(D1, OUTPUT);
  pinMode(D2, OUTPUT);
  pinMode(D3, OUTPUT);
}

void loop() {

  digit1(); one(); delay(1000);
  digit2(); two(); delay(1000);
  digit3(); three(); delay(1000);


  for (int i = 1; i <= 9; i++) {
    digit1(); displayNumber(i); delay(1000);
    digit2(); displayNumber(i); delay(1000);
    digit3(); displayNumber(i); delay(1000);
  }
}

void displayNumber(int number) {
  switch (number) {
    case 1: one(); break;
    case 2: two(); break;
    case 3: three(); break;
    case 4: four(); break;
    case 5: five(); break;
    case 6: six(); break;
    case 7: seven(); break;
    case 8: eight(); break;
    case 9: nine(); break;
  }
}

void one() {
  digitalWrite(pinA, HIGH); digitalWrite(pinB, LOW); digitalWrite(pinC, LOW);
  digitalWrite(pinD, HIGH); digitalWrite(pinE, HIGH); digitalWrite(pinF, HIGH); digitalWrite(pinG, HIGH);
}

void two() {
  digitalWrite(pinA, LOW); digitalWrite(pinB, LOW); digitalWrite(pinC, HIGH);
  digitalWrite(pinD, LOW); digitalWrite(pinE, LOW); digitalWrite(pinF, HIGH); digitalWrite(pinG, LOW);
}

void three() {
  digitalWrite(pinA, LOW); digitalWrite(pinB, LOW); digitalWrite(pinC, LOW);
  digitalWrite(pinD, LOW); digitalWrite(pinE, HIGH); digitalWrite(pinF, HIGH); digitalWrite(pinG, LOW);
}

void four() {
  digitalWrite(pinA, HIGH); digitalWrite(pinB, LOW); digitalWrite(pinC, LOW);
  digitalWrite(pinD, HIGH); digitalWrite(pinE, HIGH); digitalWrite(pinF, LOW); digitalWrite(pinG, LOW);
}

void five() {
  digitalWrite(pinA, LOW); digitalWrite(pinB, HIGH); digitalWrite(pinC, LOW);
  digitalWrite(pinD, LOW); digitalWrite(pinE, HIGH); digitalWrite(pinF, LOW); digitalWrite(pinG, LOW);
}

void six() {
  digitalWrite(pinA, LOW); digitalWrite(pinB, HIGH); digitalWrite(pinC, LOW);
  digitalWrite(pinD, LOW); digitalWrite(pinE, LOW); digitalWrite(pinF, LOW); digitalWrite(pinG, LOW);
}

void seven() {
  digitalWrite(pinA, LOW); digitalWrite(pinB, LOW); digitalWrite(pinC, LOW);
  digitalWrite(pinD, HIGH); digitalWrite(pinE, HIGH); digitalWrite(pinF, HIGH); digitalWrite(pinG, HIGH);
}

void eight() {
  digitalWrite(pinA, LOW); digitalWrite(pinB, LOW); digitalWrite(pinC, LOW);
  digitalWrite(pinD, LOW); digitalWrite(pinE, LOW); digitalWrite(pinF, LOW); digitalWrite(pinG, LOW);
}

void nine() {
  digitalWrite(pinA, LOW); digitalWrite(pinB, LOW); digitalWrite(pinC, LOW);
  digitalWrite(pinD, HIGH); digitalWrite(pinE, HIGH); digitalWrite(pinF, LOW); digitalWrite(pinG, LOW);
}

void digit1() {
  digitalWrite(D1, HIGH); digitalWrite(D2, LOW); digitalWrite(D3, LOW);
}

void digit2() {
  digitalWrite(D1, LOW); digitalWrite(D2, HIGH); digitalWrite(D3, LOW);
}

void digit3() {
  digitalWrite(D1, LOW); digitalWrite(D2, LOW); digitalWrite(D3, HIGH);
}