String Reverse with X in between each character in C Sharp Dotnet

Here is a C# Interview question I faced in an interview. This is very easy. But, I am sharing just to make all of you aware of this type of questions being asked in interviews.

Question:

Write a function named XReverse in C# that will take a string as input and return the reverse of the string with 'X' in between each characters as Output.

Solution Code:

public static string xReverse(string inputStr)
        {
            int len = inputStr.Length;
            StringBuilder revStr = new StringBuilder();

            for (int i = len - 1; i >= 0; i--)
            {
                revStr.Append(inputStr[i]);
                if (i != 0)
                {
                    revStr.Append('X');
                }
            }
            return revStr.ToString();
        }

Output:

If anybody has any other solution or has a better idea, please share as comments.