Basic Calculator in c#

HI Programmers,
Today we are going to create a small basic calculator in C#. This calculator will perform operations like Addition,Subtraction,Multiplication and Division. This is basically a Windows Application. I choose to use windows Application over the Console Application for this program because it is a User Interface and also looks good and interesting to use. Below is the C# Window Application for calculator program.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace Windows_Form_Activities
{
     public partial class Form1 : Form
     {
      int result;
      public Form1()
      {
       InitializeComponent();
      }
      private void button1_Click(object sender, EventArgs e)
      {
       if ((string.IsNullOrWhiteSpace(textBox1.Text)) || (string.IsNullOrWhiteSpace(textBox2.Text)))
       {
        MessageBox.Show("Please enter value first", "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);
        return;
       }
       else
       {
        result = Convert.ToInt32(textBox1.Text) + Convert.ToInt32(textBox2.Text);
        MessageBox.Show("Addition is " + result);
       }
      }
      private void sub_Click(object sender, EventArgs e)
      {
       if ((string.IsNullOrWhiteSpace(textBox1.Text)) || (string.IsNullOrWhiteSpace(textBox2.Text)))
       {
        MessageBox.Show("Please enter value first","Error",MessageBoxButtons.OK,MessageBoxIcon.Warning);
        return;
       }
       else
       {
       result = Convert.ToInt32(textBox1.Text) - Convert.ToInt32(textBox2.Text);
       MessageBox.Show("Subtraction is " + result);
       }
}
        private void mul_Click(object sender, EventArgs e)
        {
        if ((string.IsNullOrWhiteSpace(textBox1.Text)) || (string.IsNullOrWhiteSpace(textBox2.Text)))
        {
         MessageBox.Show("Please enter value first", "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);
         return;
        }
        else
        {
         result = Convert.ToInt32(textBox1.Text) * Convert.ToInt32(textBox2.Text);
         MessageBox.Show("Multiplication is " + result);
        }
      }
      private void div_Click(object sender, EventArgs e)
      {
        if ((string.IsNullOrWhiteSpace(textBox1.Text)) || (string.IsNullOrWhiteSpace(textBox2.Text)))
        {
         MessageBox.Show("Please enter value first", "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);
         return;
        }
        else
        {
         result = Convert.ToInt32(textBox1.Text) / Convert.ToInt32(textBox2.Text);
         MessageBox.Show("Division is " + result);
        }
      }
     }
}

Explaination

The above application program calculator performs four basic operations like addition,subtraction,Multiplication and division.

We have taken two TextBoxes and Four Buttons for four different operations respectively.

The User have to enter two numbers in two Textboxes respectively.

After entering numbers , he has to click on button of which he wants to perform operations.

The operations will be performed and the result will be appeared as messagebox to user.

From the beginning , the user first need to deisgn UI for the application and then need to write code.

There are four events for each operation

You don't need to write events separately. You just double click on button in design and that event code will be automatically generated.

In above program, We first checked whether numbers are inserted in two textboxes or not. We perform that validation using IF statement.

Then We perform the operation based on the Button clicked.