Question

[10 marks] Write a recursive method, reverse, that displays a string in a reverse order. For example, reverse("UBC-O") displays O-CBU. Use a helper method to improve the performance of your program.
Write a test program that prompts the user to enter a string and displays its reversal.

MUST HAVE A HELPER METHOD TO IMPROVE PERFORMANCE.

FOR JAVA

THANK YOU!

Answer 1

import java.util.Scanner;

public class StringReverse {

    public static void printReverseHelper(String s, int index) {
        if (index < s.length()) {
            printReverseHelper(s, index + 1);
            System.out.print(s.charAt(index));
        }
    }

    public static void printReverse(String s) {
        printReverseHelper(s, 0);
        System.out.println();
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter a string: ");
        String line = in.nextLine();
        printReverse(line);
    }
}