private void SingleOperation_Click(object sender, EventArgs e) { Button b = (Button)sender; double number = Convert.ToDouble(textBox1.Text); switch (b.Text) { case "x*x": textBox1.Text = Convert.ToString(c.Power(number)); break; case "1/x": if (number != 0) { textBox1.Text = Convert.ToString(c.Inverse(number)); } else { MessageBox.Show("На ноль делить нельзя"); MainText(); SecondaryText(); } break; case "%": if (textBox1.Text != "0") { textBox1.Text = Convert.ToString(c.Percent(number)); } break; case "sqrt": textBox1.Text = Convert.ToString(c.Sqrt(number)); break; } }