Simple Calculator

This is a very simple code just like a calculator. The purpose of this code is to teach you how to calculate two number using TextBoxes a ComboBox and a Button. I am using the switch statement and a solution to common problems on how to display integer value to a TextBox.

I decided to upload this because I found some question on the internet regarding on how to convert string to integer as well as how to convert integer to string.
The program contains a very simple code as shown below:

        private void btnCalculate_Click(object sender, EventArgs e)
        {
            int firstno = int.Parse(txtFirstNo.Text);
            int secondno = int.Parse(txtSecondNo.Text);
            int intTotal;

            intTotal = 0;

            switch (cboOperator.Text)
            {
                case "+":
                    intTotal = firstno + secondno;
                    break;
                case "-":
                    intTotal = firstno - secondno;
                    break;
                case "*":
                    intTotal = firstno * secondno;
                    break;
                case "/":
                    intTotal = firstno / secondno;
                    break;
            }

            txtTotal.Text = intTotal.ToString();
        }

The last line here is the most important code. In Visual Basic you don’t need to add ToString() function. But because C# just like c/c++ is very strict you are not allowed to directly display an integer to a TextBox.