What is classes and method

Classes & Method in ASP.NET .

protected void Page_Load(object sender, EventArgs e)

{

        //Create object of class

        CommonClass objCommonClass = new CommonClass();

        //Call sum function by passing 2 parameters

        int intSum1 = objCommonClass.Sum(10, 20);

        Response.Write("Sum1 = "+intSum1);

        //Call sum function by passing 3 parameters

        int intSum2 = objCommonClass.Sum(10, 20,30);

        Response.Write("<br/>");

        Response.Write("Sum2 = " + intSum2);

}

public class CommonClass

{

    //public is access modifier

    //int return type

    //Sum is name of function

    //x,y are the parameters

    public int Sum(int x, int y)

    {

        return x + y;

    }

    public int Sum(int x, int y, int z)

    {

        return x + y + z;

    }

}