//  DRIVER. The MAIN method has tests for your class ZILLION. Each test has a
//  comment that shows what the test should print if your code is correct. It
//  also has the number of points you will receive if the test is successful.
//  These tests are worth a total of 25 points.

class Zillion {
  private int s;
  private int[] number;
  public Zillion(int size) {
    number = new int[size];
    s = size;
  }
  public void increment(){
    int n = 0;
    boolean isCorrect = false;
    while (isCorrect==false) {
      number[n]+=1;
      if (number[n] >= 10) {
        number[n]=0;
        if (n<(s-1)) {
          n+=1;
        }
        else {
          isCorrect = true;
        }
      }
      else {
        isCorrect=true;
      }
    }

  }
  public String toString(){
    String test = "";
    for (int n=(s-1); n>=0; n-=1) {
      test+=number[n];
    }
    return test;
  }
}

class Driver
{
  public static void main(String[] args)
  {
    Zillion z = new Zillion(2);
    System.out.println(z);  //  00  2 points

    z.increment();
    System.out.println(z);  //  01  2 points

    z.increment();
    System.out.println(z);  //  02  2 points

    z.increment();
    z.increment();
    z.increment();
    z.increment();
    z.increment();
    z.increment();
    z.increment();
    z.increment();

    System.out.println(z);  //  10  2 points
    z.increment();
    System.out.println(z);  //  11  2 points

    z = new Zillion(4);
    System.out.println(z);  //  0000  2 points

    for (int j = 1; j <= 999; j += 1)
    {
      z.increment();
    }
    System.out.println(z);  //  0999  2 points

    z.increment();
    System.out.println(z);  //  1000  2 points

    for (int j = 1; j <= 999; j += 1)
    {
      z.increment();
    }
    System.out.println(z);  //  1999  2 points

    z.increment();
    System.out.println(z);  //  2000  2 points

    for (int j = 1; j <= 7999; j += 1)
    {
      z.increment();
    }
    System.out.println(z);  //  9999  2 points

    z.increment();
    System.out.println(z);  //  0000  2 points

    z.increment();
    System.out.println(z);  //  0001  1 point
  }
}