how to get sum of the numbers in C# .net using Recursive Function

    protected void btnSubmit_Click(object sender, EventArgs e)

    {

        string newNumber = string.Empty;

        newNumber = CalculateRecords(txtNumber.Text).ToString();

        lblMessage.Text = newNumber.ToString();

    }
   
Mormal Method
     

    private int CalculateRecords(string test)

    {

        try

        {

            int y = 0;

            string calculatedText = string.Empty;

        Label:

            if (calculatedText != null && calculatedText != string.Empty)

            {

                test = calculatedText;

                y = 0;

            }

            string[] x = new string[test.Length];

            for (int i = 0; i < test.Length; i++)

            {

                x[i] = test.Substring(i, 1);

                y += int.Parse((x[i]));

            }

            string j = y.ToString();

            string[] z = new string[j.Length];

            if (z.Length > 1)

            {

                calculatedText = j;

                goto Label;

            }

            return y;

        }

        catch (Exception ex)

        {

            throw ex;

        }

    }

Input:"123456789"
Output:9


Recursive Function Method

Recursive Function is a Function that call itself.

private int CalculateRecords(string test)

    {

        try

        {

            int y = 0;

            if (test.Length > 1)

            {

                string[] x = new string[test.Length];

                for (int i = 0; i < test.Length; i++)

                {

                    x[i] = test.Substring(i, 1);

                    y += int.Parse((x[i]));

                }

                test = Convert.ToString(CalculateRecords(y.ToString()));

            }

            return Convert.ToInt32(test);

        }

        catch (Exception ex)

        {

            throw ex;

        }

    }