Confusion of access level of variables in static method.

Question

using System;

namespace ConsoleApplication19
{
    class Program
    {
         int a = 10;
       static int b = 10;

        static void myfun()
        {
              int j = 10;

             Console.WriteLine("Hello {0}",j); // valid
             Console.WriteLine("Hello {0}", a); //invalid
             Console.WriteLine("Hello {0}", b); //valid
       }

     static void Main(string[] args)
     {
            myfun();
          Console.ReadKey();
    }
}
}

pritaeas · Answer

Before obj2 = obj; they have their own memory space. After obj2 = obj; they both point to the same memory space.

Ashvani chaudhary · Answer

If i allocate a new instance with obj2 then its having same problem . is it still point to same object reference .even i have give a different memory and instance to obj2 class Program { string name = string.Empty; static void Main(string[] args) { Program obj = new Program(); Program obj2 = new Program(); obj.name = ashu; obj2 = obj; Console.WriteLine(obj2.name); Console.ReadKey(); } }

Ashvani chaudhary · Answer

pritaeas I have a question please give me conclusion of this . class Program { string name = string.Empty; static void Main(string[] args) { Program obj = new Program(); Program obj2 =Program(); obj.name = ashu; obj2 = obj; Console.WriteLine(obj2.name); Console.ReadKey(); } } Why obj2 hold name ashu here ....what is the concept

Ashvani chaudhary · Answer

Pritaeas Thanks Now i got the concept

pritaeas · Answer

The local variable gets its memory when the method is initialized each time you call it. So it is NOT initialized with the static variable.

pritaeas · Answer

That one is a local variable (not an instance variable) it is recreated every time the method is called.

Ashvani chaudhary · Answer

But my question is if a Static function can accept static class variable only because static variable gets memory at program execution start but non static variable in static function ...how does they get memory and valid inside static function

Manas Mohapatra · Answer

Hi Let's discuss why it is not accessible: When you declare -> int a = 10; By default access specifier is private. Secondly if you want access the value then access like: Console.WriteLine(Hello {0} new Program().b); Secondly you are trying to access the variable(b) inside static method so it needs a static variable or instance of a object. If you check same thing by declaring a a normal function(without static) then you can access that variable directly without creating instance. When you declare static int b = 10; When you declare a variable as static then you can access this value without creating object. Because static always stay in memory and it dies when application stops.

Ashvani chaudhary · Answer

Here obj and obj2 have same memory location (i mean pointing to same memory location) or obj2 have its own memory location other then obj and have memory address in obj2 memory location

pritaeas · Answer

Initially yes. Program obj = new Program(); Program obj2 = new Program(); // here you create a new instance different from obj obj.name = ashu; obj2 = obj; // here you tell obj2 to point to obj thus removing it's original different values

pritaeas · Answer

With obj2 = obj1 you make a reference to obj1. You now have two variables pointing to the same class instance. Changes to one are visible in both.

Ashvani chaudhary · Answer

As per the definition of c# only static data members get memory when a class loads so a local variable also get initialize with static member get initialize ? As well i heard only static member get memory when a class load so why a local variable get memory without class object initialization. Then what is the difference and benefit of initialization of static variables

pritaeas · Answer

Yes. There is also const and readonly of course. const is accessible by static and instance methods alike. readonly differs between non-static and static like a regular variable.

Ashvani chaudhary · Answer

Ok fine and thanks for explanation sir. So as per the information you have given to me .There are three type of variable scope 1 ) Local Variable 2) Static variable 3) Instance variable am i right sir ....

Ashvani chaudhary · Answer

But in myfun() static method there is an instance variable int J which is not static but working fine ....so from where and when get memory because as we know it is instance variable and instance variable always get memory at the time of initialize an object of class

pritaeas · Answer

They get initialized when an object is instantiated with new. These variables are not accessible in a static method.

Raja T · Answer

HiA field declared with the static modifier is called a static variable.static variable shared the value of it among all instances of the class. int a =10 and static int b=10; It is outside of the myfun() and int j=10 is inside of the function So here j is valid b is valid why means b is static variable means you can access any where of the this class means(inside the funtionoutside the function) and finaly a is invalid why means by default a cess specifier is private it can not access outside of the class. Please check out more details of static variable https://msdn.microsoft.com/en-us/library/aa691162(v=vs.71).aspx http://stackoverflow.com/questions/10795502/what-is-the-use-of-static-variable-in-cwhen-to-use-itwhy-cant-i-declare-the-s

pritaeas · Answer

A static method can only read static variables from it's class (and constants) but not instance variables. An instance variable (a) is only accessible from an object/class instance not from the class.