SWEN 6301 - Assignment 4 - Problem 1

StringPermutator.java

import java.util.Scanner;

public class StringPermutator {
	
	public static void permutate(String string) {
        int [] factorials = new int[string.length()+1];
        factorials[0] = 1;
        for (int i = 1; i<=string.length();i++) {
            factorials[i] = factorials[i-1] * i;
        }

        for (int i = 0; i < factorials[string.length()]; i++) {
            String onePermutation="";
            String temp = string;
            int positionCode = i;
            for (int position = string.length(); position > 0 ;position--){
                int selected = positionCode / factorials[position-1];
                onePermutation += temp.charAt(selected);
                positionCode = positionCode % factorials[position-1];
                temp = temp.substring(0,selected) + temp.substring(selected+1);
            }
            System.out.println(onePermutation);
        }
	}

	public static void main(String[] args) {
		System.out.print("Enter string to permutate: ");
		Scanner scanner = new Scanner(System.in);
		String string = scanner.nextLine();
		scanner.close();
		permutate(string);
	}
	
}

This code is adopted from https://stackoverflow.com/a/11471673. It performs iterative approach to string permutations.