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

Here's a high level example I wrote which illustrates the human language explanation Peter gave:

    public List FindPermutations(string input)
    {
        if (input.Length == 1)
            return new List { input };
        var perms = new List();
        foreach (var c in input)
        {
            var others = input.Remove(input.IndexOf(c), 1);
            perms.AddRange(FindPermutations(others).Select(perm => c + perm));
        }
        return perms;
    }