private void EqualButton_Click(object sender, EventArgs e) { if (isOperation) { secondV = Convert.ToDouble(textBox1.Text); } else { label2.Text = textBox1.Text; isEqual = true; return; } label2.Text = c.FirstValue + c.Operation + Convert.ToString(secondV); isEqual = true; isOperation = false; switch (c.Operation) { case "+": textBox1.Text = Convert.ToString(c.Plus(secondV)); break; case "-": textBox1.Text = Convert.ToString(c.Minus(secondV)); break; case "*": textBox1.Text = Convert.ToString(c.Multiply(secondV)); break; case "/": if (secondV != 0) { textBox1.Text = Convert.ToString(c.Divide(secondV)); } else { MessageBox.Show("На ноль делить нельзя"); isEqual = false; MainText(); SecondaryText(); c = new Calculate(); } break; } }