Question

I am trying to create a string that inserts a duplicate letter from the original into the modified. For example, the output of one run would be:

Original word:

stack

Output:

sstack, sttack, staack, stacck, stackk

Does that make sense? I have this so far, and I feel i am close, but I am suing the wrong method to reassemble the string. Any help would be appreciated:

 // Use ToCharArray to convert string to array.                
 char[] array = originalWord.ToCharArray();

 // Loop through array.
 for (int i = 0; i < array.Length; i++)
 {
    // Get character from array.
    char letter = array[i];
    string result = array.ToString();
    string result2 = string.Join("", result.Select(x => x + letter));
    Console.Write(result2);
 }

Answer 1

This should work:

var original = "stack";
for (int i = 0; i < original.Length; i++)
    Console.WriteLine(original.Insert(i, original[i].ToString()));