Подскажите, как работает метод - C#

        private  void min(double a, double b,double s)
        {
 
            if (a > b) { s = b; } else s = a;
          
        }
   
        private void button1_Click(object sender, EventArgs e)
        {
            double v,aa,bb, u, C;
            aa = Convert.ToDouble(textBox1.Text);
         bb = Convert.ToDouble(textBox1.Text);
            u = min(aa,bb);
            v = min(aa * bb, aa + bb);
           textBox3.Text = Convert.ToString(u);
        }