Modulus to display input number vertically

Question

Basically I need to write a program in java that will ask the user for an integer, and then display that number vertically (using only math), so the number 2849 will display:

2

8

4

9

I know that I can use modulus by 10, getting 9, 4, 8, 2 but what I do not know is how to write code that will carry over the new value after the first modulus to keep going.

import java.util.Scanner;

public class HorizToVert {
   public static void main(String[] args) {
      Scanner input = new Scanner(System.in);
      System.out.print("Enter a number: ");
      int answer = input.nextInt();
         System.out.print(answer%10);


   }//close main
}//close class

That's what I have so far. As I said, I know that it will give me the first remainder. So say the user enters 4936. I know the first modulus gets me 6. I don't know how to go to 493 after I do that first modulus to continue the process. Any help would be great!

So I realized that division is the actual way I should approach this, because modulus will give me the reverse of the input. But I still don't know how to get to the second interval. — Devin, May 06 '15 at 22:16

score 0 · Answer 1 · answered Sep 01 '20 at 14:09

You need to use a combination of modulus and division. The modulus will strip away what's above the digit; while the division while strip away what is below the digit.

int answer = input.nextInt();

if (answer < 0)
{
    System.out.print("-");
    answer = answer * -1; // make it positive for the loop
}

for (int exponent = 1; answer > 0; exponent = exponent + 1)
{
    int mod = answer % Math.pow(10, exponent); //strip away digits above the desired digit.
    int digit = mod / Math.pow(10, exponent - 1); //strip away digits below the desired digit and bring the desired digit into the [0 - 9] range.
    System.out.print(digit);

    answer = answer - mod; //needed for loop control.
}

score 0 · Answer 2 · answered Sep 01 '20 at 14:16

As you correctly observe, modulo 10 will only return the last digit.

So have to write a loop to get each digit in turn, divide the non-remainder by 10 and repeat. Finally reverse the list for printing.

An easier approach might use the string conversion, where you can simply print digit character by digit character.

Modulus to display input number vertically

2 Answers2