String Permutation Write a recursive method to print all the

(String Permutation) Write a recursive method to print all the permutations of a string. For example, for string abc, the permutation is

abc

acb

bac

bca

cab

cba

(Hint: Define the following two methods. The second is a helper method.) public static void displayPermutation(String s) public static void displayPermutation(String s1, String s2) The first method simply invokes displayPermutation(“ “, s). The second method uses a loop to move a character from s2 to s1 and recursively invokes it with a new s1 and s2. The base is that S2 is empty and prints s1 to the console. Write a test program that prompts the user to enter a string and displays all its permutations.

Solution

import java.util.Scanner;

public class Stringpermutation{

public static void main(String[] args) {

System.out.print(\"Enter a string: \");

String s = new Scanner(System.in).next();

System.out.println(\"All possible permutations of \" + s + \" are: \");

displayPermutation(s);

}

public static void displayPermutation(String s) {

displayPermutation(\"\", s);

}

public static void displayPermutation(String s1, String s2) {

if (s2.length() == 0) {

System.out.println(s1);

} else {

for (int i = 0; i < s2.length(); i++) {

displayPermutation(s1 + s2.charAt(i), s2.substring(0, i) + s2.substring(i + 1));

}

}

}

}