public class IterativeDemo1
{
    public static void main(String[] args)
    {
        System.out.println("writeVertical(3):");
        writeVertical(3);

        System.out.println("writeVertical(12):");
        writeVertical(12);

        System.out.println("writeVertical(123):");
        writeVertical(123);
    }

    public static void writeVertical(int n)
    {
        int nsTens = 1;
        int leftEndPiece = n;
        while (leftEndPiece > 9)
        {
            leftEndPiece = leftEndPiece/10;
            nsTens = nsTens*10;
        }
        //nsTens is a power of ten that has the same number
        //of digits as n. For example, if n is 2345, then
        //nsTens is 1000.

        for (int powerOf10 = nsTens;
               powerOf10 > 0; powerOf10 = powerOf10/10)
        {
            System.out.println(n/powerOf10);
            n = n%powerOf10;
        }
    }
}