Listing all permutations of a string/integer

Question

A common task in programming interviews (not from my experience of interviews though) is to take a string or an integer and list every possible permutation.

Is there

Answer 1

The below is my implementation of permutation . Don't mind the variable names, as i was doing it for fun :)

class combinations
{
    static void Main()
    {

        string choice = "y";
        do
        {
            try
            {
                Console.WriteLine("Enter word :");
                string abc = Console.ReadLine().ToString();
                Console.WriteLine("Combinatins for word :");
                List final = comb(abc);
                int count = 1;
                foreach (string s in final)
                {
                    Console.WriteLine("{0} --> {1}", count++, s);
                }
                Console.WriteLine("Do you wish to continue(y/n)?");
                choice = Console.ReadLine().ToString();
            }
            catch (Exception exc)
            {
                Console.WriteLine(exc);
            }
        } while (choice == "y" || choice == "Y");
    }

    static string swap(string test)
    {
        return swap(0, 1, test);
    }

    static List comb(string test)
    {
        List sec = new List();
        List first = new List();
        if (test.Length == 1) first.Add(test);
        else if (test.Length == 2) { first.Add(test); first.Add(swap(test)); }
        else if (test.Length > 2)
        {
            sec = generateWords(test);
            foreach (string s in sec)
            {
                string init = s.Substring(0, 1);
                string restOfbody = s.Substring(1, s.Length - 1);

                List third = comb(restOfbody);
                foreach (string s1 in third)
                {
                    if (!first.Contains(init + s1)) first.Add(init + s1);
                }


            }
        }

        return first;
    }

    static string ShiftBack(string abc)
    {
        char[] arr = abc.ToCharArray();
        char temp = arr[0];
        string wrd = string.Empty;
        for (int i = 1; i < arr.Length; i++)
        {
            wrd += arr[i];
        }

        wrd += temp;
        return wrd;
    }

    static List generateWords(string test)
    {
        List final = new List();
        if (test.Length == 1)
            final.Add(test);
        else
        {
            final.Add(test);
            string holdString = test;
            while (final.Count < test.Length)
            {
                holdString = ShiftBack(holdString);
                final.Add(holdString);
            }
        }

        return final;
    }

    static string swap(int currentPosition, int targetPosition, string temp)
    {
        char[] arr = temp.ToCharArray();
        char t = arr[currentPosition];
        arr[currentPosition] = arr[targetPosition];
        arr[targetPosition] = t;
        string word = string.Empty;
        for (int i = 0; i < arr.Length; i++)
        {
            word += arr[i];

        }

        return word;

    }
}