using System;

​

public class PermutationGenerator {

    private char[] charList;

    public string input { 

        get { 

            return this.charList.ToString();

            }

        set {

            charList = value.ToCharArray();

            }

        }

    public PermutationGenerator(string input) {

        this.input = input;

    }

    private void Swap( int a,  int b) {

        char temp = charList[a];

        charList[a]=charList[b];

        charList[b]=temp;

    }

    public void Generate(int index) {

        if(index == charList.GetLength(0)) {

            Console.WriteLine(charList);

        }

        for(int i = index; i < charList.GetLength(0); i++ ) {

            Swap( i,  index);

            Generate(index+1);

            Swap( index,  i);

        }

    }

}

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        PermutationGenerator generator = new PermutationGenerator("abc");

        generator.Generate(0);

    }

}