What is the difference between Variable block scope and Class block scope

its better that i will explain you with an example

    public partial class Form1 : Form

    {

       int i;

        public Form1()

        {

            InitializeComponent();

            i = 10;

            // when we access i , it will be accessible, because it is in

            // class scope variable, it will be alive till the life of

            // object.

            int j = 10;

            // here j scope is within the block( between this { }) only

            // whenver block is completer it will not be acceccese outsite(see form1_load event).

            // it will not be more alive.

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            i = 20;

            //j =20;

            // when we write statement j=20, it will give as error

            // because there is no variable named "j"

        }

}