User input a word then print letters of the word on a new line for java

Question

I need help using just String method, indexOf, substring, accumulators, while loops. I want the user to input a word using JOptionPane.showInputDialog and will display each letter of word on a new line in the output. How do you do this in java?

Ex.

Input: Dog

Output:

D
o
g

Here's my code so far (it really needs correcting):

import javax.swing.*;
public class Exercise_28 {
    public static void main(String[] args) {
        String input;
        String letters;
        int num1;
        int num2;

        input = JOptionPane.showInputDialog("Enter a word: ");
        num1 = input.length() - 1;
        num2 = input.length() - num1 - 1;
        letters = input.substring(0, 1);

        while (num2 <= num1) {
            System.out.println(letters);
            num2++;
            letters = input.substring(num2, num2 + 1);
        }
        System.exit(0);
    }
}

Answer 1

You can change your code like that

 import javax.swing.*;
public class Exercise_28 {
    public static void main(String[] args) {
        String input;
        String letters;
        int num1;
        int num2;

        input = JOptionPane.showInputDialog("Enter a word: ");
        num1 = input.length() - 1;
        num2 = input.length() - num1 - 1;
           //  letters = input.substring(0, 1);

    while (num2 <= num1) {
        letters = input.substring(num2, num2 + 1);
        System.out.println(letters);
        num2++;
    }
    System.exit(0);
    }
}

error occurs when you want substring input without checking your num2 with while