C# da While Şart ile İşlem Yapma

c#

private void button1_Click(object sender, EventArgs e)

        {

            int n, s = 1, f = 0, islem;

            n = Convert.ToInt32(textBox1.Text);

            while (s<=n)

            {

                if (s % 2 == 0)

                {

                    islem = s * s * s;

                }

                else

                {

                    islem = s * s;

                }

                f = f + islem;

                s++;

            }

            label3.Text = f + "   ";

        }