C#ReverseString

public static class Exercise
{
    public static string ReverseString(string inputStr)
    {
        var input = new StringBuilder(inputStr);
        var output = new StringBuilder();
        for (var i = inputStr.Length-1; i >= 0; i--)
        {
            output.Append(inputStr[i]);
        }

        return output.ToString();
    }
}