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 is the function which will print all permutations recursively.

public void Permutations(string input, StringBuilder sb)
    {
        if (sb.Length == input.Length)
        {
            Console.WriteLine(sb.ToString());
            return;
        }

        char[] inChar = input.ToCharArray();

        for (int i = 0; i < input.Length; i++)
        {
            if (!sb.ToString().Contains(inChar[i]))
            {
                sb.Append(inChar[i]);
                Permutations(input, sb);    
                RemoveChar(sb, inChar[i]);
            }
        }
    }

private bool RemoveChar(StringBuilder input, char toRemove)
    {
        int index = input.ToString().IndexOf(toRemove);
        if (index >= 0)
        {
            input.Remove(index, 1);
            return true;
        }
        return false;
    }