byte countDigits(int num){
  byte count=0;
  while(num){
    num=num/10;
    count++;
  }
  return count;
}

int getDigit(unsigned int number, int digit) {
    for (int i=0; i<digit-1; i++) { 
      number /= 10; 
    }
    return number % 10;
}

#define MAX_NUMBER_OF_DIGITS 5
byte array_to_hold_digit[MAX_NUMBER_OF_DIGITS];
 
void setup(void) {
  Serial.begin(9600);
  extractDigit_Save2Arrary(5678);
  Serial.println(array_to_hold_digit[0]);
  Serial.println(array_to_hold_digit[1]);
  Serial.println(array_to_hold_digit[2]);
  Serial.println(array_to_hold_digit[3]);
}
 
void loop(void) {
 
}
 
/*----------------------------------------------------------------------------
 count number of digits in a number(integer)
----------------------------------------------------------------------------*/
void extractDigit_Save2Arrary(int number){
  byte number_of_digit = countDigits(number); 
  for (byte i=0; i<number_of_digit; i++) {  
     array_to_hold_digit[i] = getDigit(number,number_of_digit-i); //store each digit to array
  }
 
  /*
  for (byte i=0; i<number_of_digit; i++) {  
     Serial.print(array_to_hold_digit[i]);
  }
  Serial.println();
  */
}
 
/*----------------------------------------------------------------------------
 count number of digits in a number(integer)
----------------------------------------------------------------------------*/
byte countDigits(int number){
  byte count=0;
  while(number){
    number=number/10;
    count++;
  }
  return count;
}
 
/*----------------------------------------------------------------------------
 extract a digit from an number(integer)
----------------------------------------------------------------------------*/
byte getDigit(unsigned int number, int digit) {
    for (int i=0; i<digit-1; i++) { 
      number /= 10; 
    }
    return number % 10;
}