const int A = 2;
const int B = 3;
const int C = 4;
const int D = 5;
const int E = 6;
const int F = 7;
const int G = 8;
const int BUTTON = 9;

int c = 0;
int up = 0;
int last = 0;

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

void loop() 
{
  up = digitalRead(BUTTON);
  if (up != last) 
  {
    if (up == HIGH) 
    {
      if(c == 9)
      {
        c = -1;
      }
      c++;
      changeNumber(c);
      delay(300);
    } 
    delay(50);
  }
  changeNumber(c);
}

void changeNumber(int n)
{
  switch(n)
  {
    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;
  }
}