A simple algorithm

After Lipis's comment on my previous post about the words with shuffled letters, I thought it might be nice to post a simple algorithm for that.

The C# method below takes as argument a string and returns a string that contains the same letters but only the first and the last are guaranteed to be at the right position.

private string shuffle(string word)
{
  Random rnd = new Random();
  int index;
  string temp = "";

  int loop = word.Length - 1;

  //loop the word without the first and last letters.
  for (int i = 1; i < loop; i++)
  {
    //get an int from 1..word.Length-1.
    index = rnd.Next(1,word.Length-1);

    //add the char at this index to the temp.
    temp = temp + word[index];

    //delete the char at this index from word.
    word = word.Remove(index, 1);
  }

  return word[0] + temp + word[word.Length-1];
}

With the definition I gave, this method is almost correct.
There are some known bugs but I didn't want to make the code difficult to grasp.
Now that the code is easy to understand, I can talk about the bugs and the solutions.

1. If the word is only a letter (such as 'a'), the method returns this letter twice.
The solution is to check the length of the word given. So after initializing loop variable, write:
if (loop == 0) return word;

2. There is a possibility that the word returned is the same with the one given.
As the length of the word increases, this possibility becomes smaller. But for 4-letter words, it's 50%. What one could do, is to check if the word about to return, is the same with the one provided, and loop until they are different.