Thread: How to convert a digit to words

I am trying to figure out how to convert digits from 0 to 9 to words in my program.
What is the proper code to do this?

I have found examples online but none of them are working with my code.
What is just a generic example? I need to do it inside a switch statement too.

switch (operation)
        {
            case "+":
                System.out.println("The sum of ");
        }

I need to take my input of numbers from the user as digits and change them to words in this system.out statement.

import java.util.*;
 
public class StudentInformation
{ 
    public static void main (String [] args)
    {
        Scanner scan = new Scanner (System.in);
 
        System.out.println("Please enter the first number between 0 and 9: ");
        int num1 = scan.nextInt();
 
        System.out.println("\nPlease enter the second number between 0 and 9: ");
        int num2 = scan.nextInt();
 
        System.out.println("\nPlease enter your operator: + for ADDITION, - for SUBTRACTION, * for MULTIPLICATION,");
        System.out.println("/ for DIVISION, or ^ for EXPONENTIATION: ");
        String operation = scan.next();
 
        if (num1 < 0 || num1 > 9 || num2 < 0 || num2 > 9)
        {
            System.out.println("\nInvalid Number");
        }
 
        NumberToWords num = new NumberToWords();
 
        switch (operation)
        {
            case "+":
                System.out.println("The sum of " + num.convert(num1) + " and " + num.convert(num2) + " is " + (num1 + num2));
                break;
            case "-":
                System.out.println("The difference of ");
                break;
            case "*":
                System.out.println("The product of ");
                break;
            case "/":
                System.out.println("The quotient of ");
                break;
            case "^":
                System.out.println("The expontentiation of ");
                break;
            default:
                System.out.println(operation + " is not valid.");
        }
 
    }
}

I am not sure how to write an array and have looked it up. Where is it supposed to be located at in my program? I need to convert the user input integers into words for the system.out statements in the switch loop.
Thanks