How to use Checked and Unchecked Operators in C#

There are two operators used in c# to handle the overflow exception control as given below.

1. Checked Operator
2. Unchecked Operator

1.) Checked Operator :-
C# provides the checked and Unchecked operators.If we use checked operator in codes, the CLR will enforce overflow checking and throw an exception if an overflow occurs.  Example:-

private void button1_Click(object sender, EventArgs e)
        {
            byte m = 255;
            checked
            {
                m++;
            }
            MessageBox.Show(m.ToString());
        }




Output :-OverflowException was Unhandled
If we run this codes then we will get an error message. I will show it later.
Note :-
The Byte data type can only hold values in the range 0 to 255 ,so incrementing the value of m causes an overflow.
1.) UnChecked Operator :-
If we want to suppress overflow checking, we can use Unchecked operator.In this case, no exception will be raised,but we will lose our data.We already know that ,the byte type can't hold a value of greater than 255.So the overflow bits will be discarded.Variable m hold a value of zero.
Example:-

private void button2_Click(object sender, EventArgs e)
        {
            byte m = 255;
            unchecked
            {
                m++;
            }
            MessageBox.Show("m=" +m.ToString());
        }

Output :- m=0

There are some steps to implement this whole concepts as given below:-
Step 1:- First open your visual studio --> File  -->New  -->Project  -->Select WindowsFormsApplication  --> OK.
Step 2:- Now drag and drop two button on the page from the toolbox as shown below:- 

Step 3:- Now Double click on each button (Checked & Unchecked) and write the c# codes as given below:-

using System;
using System.Windows.Forms;
namespace checked_operaors
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            byte m = 255;
            checked
            {
                m++;
            }
            MessageBox.Show(m.ToString());
        }

        private void button2_Click(object sender, EventArgs e)
        {
            byte m = 255;
            unchecked
            {
                m++;
            }
            MessageBox.Show("m=" +m.ToString());
        }
    }
}

Step 4:-  Now Run the application  --> Press press Checked Button  --> You will get an error message as shown below:-

Step 5:-  Now press Unchecked button --> You will value of m=0.It means you lose the values.

Note:-Whenever there is a risk of an unintentional overflow ,we really need some way of making sure that we get the result as we want.

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