Create a new String with Duplicate Letters

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()));

Answer 2

You can use String.Insert to insert a string at a given index into another string.

IEnumerable<string> strings = originalWord
    .Select((c, idx) => originalWord.Insert(idx, c.ToString()));

Answer 3

Fixed :

        string originalWord = "stack";
        // 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 = originalWord.Insert(i, letter.ToString(CultureInfo.InvariantCulture));
            Console.WriteLine(result);
        }

The Linq way :

IEnumerable<string> words = originalWord.Select((letter, i) => originalWord.Insert(i, letter.ToString(CultureInfo.InvariantCulture)));

Answer 4

You can use String.Insert() method like;

string s = "stack";

for (int i = 0; i < s.Length; i++)
{
   Console.WriteLine (s.Insert(i, s[i].ToString()));
}

Here is a DEMO.

Oh god, already aded 3 answers when I writing it. Damn..