int A = 2;
int B = 3;
int C = 4;
int D = 5;
int E = 7;
int F = 8;
int G = 9;

int switchUpPin = 10;
int counter = 0;
int buttonUpState = 0;
int lastButtonUpState = 0;

void setup() {
  Serial.begin(9600);
  pinMode(A, OUTPUT);
  pinMode(B, OUTPUT);
  pinMode(C, OUTPUT);
  pinMode(D, OUTPUT);
  pinMode(E, OUTPUT);
  pinMode(F, OUTPUT);
  pinMode(G, OUTPUT);
}

void loop() {
  buttonUpState = digitalRead(switchUpPin);

  if (buttonUpState != lastButtonUpState) {
    if (buttonUpState == HIGH) {
      if(counter == 9){
        counter = -1;
      }
      counter++;
      changeNumber(counter);
      delay(300);
    } else {
        Serial.println("OFF");
    }
   delay(50);
  }
  changeNumber(counter);
}

void changeNumber(int buttonPress){
  switch (buttonPress){
    case 0:
      digitalWrite(A, LOW);
      digitalWrite(B, LOW);
      digitalWrite(C, LOW);
      digitalWrite(D, LOW);
      digitalWrite(E, LOW);
      digitalWrite(F, LOW);
      digitalWrite(G, HIGH);
      break;
    case 1:
      digitalWrite(A, HIGH);
      digitalWrite(B, LOW);
      digitalWrite(C, LOW);
      digitalWrite(D, HIGH);
      digitalWrite(E, HIGH);
      digitalWrite(F, HIGH);
      digitalWrite(G, HIGH);
      break;
    case 2:
      digitalWrite(A, LOW);
      digitalWrite(B, LOW);
      digitalWrite(C, HIGH);
      digitalWrite(D, LOW);
      digitalWrite(E, LOW);
      digitalWrite(F, HIGH);
      digitalWrite(G, LOW);
      break;
    case 3:
      digitalWrite(A, LOW);
      digitalWrite(B, LOW);
      digitalWrite(C, LOW);
      digitalWrite(D, LOW);
      digitalWrite(E, HIGH);
      digitalWrite(F, HIGH);
      digitalWrite(G, LOW);
      break;
    case 4:
      digitalWrite(A, HIGH);
      digitalWrite(B, LOW);
      digitalWrite(C, LOW);
      digitalWrite(D, HIGH);
      digitalWrite(E, HIGH);
      digitalWrite(F, LOW);
      digitalWrite(G, LOW);
      break;
    case 5:
      digitalWrite(A, LOW);
      digitalWrite(B, HIGH);
      digitalWrite(C, LOW);
      digitalWrite(D, LOW);
      digitalWrite(E, HIGH);
      digitalWrite(F, LOW);
      digitalWrite(G, LOW);
      break;
    case 6:
      digitalWrite(A, LOW);
      digitalWrite(B, HIGH);
      digitalWrite(C, LOW);
      digitalWrite(D, LOW);
      digitalWrite(E, LOW);
      digitalWrite(F, LOW);
      digitalWrite(G, LOW);
      break;
    case 7:
      digitalWrite(A, LOW);
      digitalWrite(B, LOW);
      digitalWrite(C, LOW);
      digitalWrite(D, HIGH);
      digitalWrite(E, HIGH);
      digitalWrite(F, HIGH);
      digitalWrite(G, HIGH);
      break;
    case 8:
      digitalWrite(A, LOW);
      digitalWrite(B, LOW);
      digitalWrite(C, LOW);
      digitalWrite(D, LOW);
      digitalWrite(E, LOW);
      digitalWrite(F, LOW);
      digitalWrite(G, LOW);
      break;
    case 9:
      digitalWrite(A, LOW);
      digitalWrite(B, LOW);
      digitalWrite(C, LOW);
      digitalWrite(D, LOW);
      digitalWrite(E, HIGH);
      digitalWrite(F, LOW);
      digitalWrite(G, LOW);
      break;
  }
}