int a = 2;
int b = 3;
int c = 4;
int d = 5;
int e = 6;
int f = 7;
int g = 8;
int common_collector_1 = 11;
int common_collector_2 = 12;
int j = 0;
int p = 0;

void setup()
{
  pinMode(a, OUTPUT);
  pinMode(b, OUTPUT);
  pinMode(c, OUTPUT);
  pinMode(d, OUTPUT);
  pinMode(e, OUTPUT);
  pinMode(f, OUTPUT);
  pinMode(g, OUTPUT);
  pinMode(common_collector_1, OUTPUT);
  pinMode(common_collector_2, OUTPUT);

}

void zero(){
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, LOW);
}

void one(){
  digitalWrite(a, LOW);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
}

void two(){
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, LOW);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, LOW);
  digitalWrite(g, HIGH);
}

void three(){
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, HIGH);
}

void four(){
  digitalWrite(a, LOW);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
}

void five(){
  digitalWrite(a, HIGH);
  digitalWrite(b, LOW);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, LOW);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
}

void six(){
  digitalWrite(a, HIGH);
  digitalWrite(b, LOW);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
}

void seven(){
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, LOW);
  digitalWrite(e, LOW);
  digitalWrite(f, LOW);
  digitalWrite(g, LOW);
}

void eight(){
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, HIGH);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
}

void nine(){
  digitalWrite(a, HIGH);
  digitalWrite(b, HIGH);
  digitalWrite(c, HIGH);
  digitalWrite(d, HIGH);
  digitalWrite(e, LOW);
  digitalWrite(f, HIGH);
  digitalWrite(g, HIGH);
}

void display_seg(int col1, int col2){
    digitalWrite(col1, LOW);
    digitalWrite(col1, HIGH);
    switch(j) {
        case 0:
        zero();
        break;
        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 display_seg1(){
//   digitalWrite(ok1, LOW);
//   digitalWrite(ok2, HIGH);
//   switch(j) {
//     case 0:
//         zero();
//         break;
//    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 display_seg2(){
//   digitalWrite(ok1, HIGH);
//   digitalWrite(ok2, LOW);
//   switch(p) {
//     case 0:
//         zero();
//         break;
//    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 loop()
{
  for(int i = 0; i < 50; i++){
    //display_seg1();
    display_seg(common_collector_1,common_collector_2);
    delay(10);
    //display_seg2();
    display_seg(common_collector_2,common_collector_1);
    delay(10);
  }
  j++;
  if(j > 9){
    j = 0;
    p++;
  }
  if(p > 9)p = 0;
}