RECURSIVE ALGORITHM TO PRINT ALL THE CHARACTERS IN A STRING IN REVERSE - ONE CHARACTER PER LINE

If the string is empty then nothing is printed.This becomes the base case.

For the recursive case, consider the string which will have two parts: first character and the remaining string.
We consider the substring except the first character and pass it as an argument to our print method. This method further breaks the input into the first character and the remaining portion of the string. The second part is thus recursively broken down until only one character is left and which gets printed.

Consider the string "WARDEN"

WARDEN = W + ARDEN

ARDEN = A + RDEN

RDEN = R + DEN

DEN = D + EN

EN = E + N

N = N (PRINT)

THEN PRINT(E)

AND SO ON.

RecursivePrintString(X1X2....Xn)
1 If X is empty then print nothing
2 else
3 RecursivePrintString(X2...Xn)

JAVA IMPLEMENTATION

import java.util.Scanner;

/**
 * Created by Ganesh.r.hegde on 15-Feb-18.
 */
public class RecursivePrintChars {

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);
        System.out.println("Enter the string whose characters are required to be printed in reverse : ");

        String text= scan.nextLine();

        //display result to the user
        System.out.println("The characters of string "+text+" in reverse is displayed below :");

        //method call
        strPrintReverse(text);
    }

    /** Recursive method strPrintReverse
     post: The argument string is displayed in reverse,
     one character per line.
     @param str The string
     */
    public static void strPrintReverse(String str) {

        if (str == null || str.isEmpty()) {
            return;
        } else {
            strPrintReverse(str.substring(1));
            System.out.println(str.charAt(0));
        }
    }

}