c# : console application - static methods

Question

why in C#, console application, in "program" class , which is default, all methods have to be static along with

static void Main(string[] args) 

Answer 1

Member functions don't have to be static; but if they are not static, that requires you to instantiate a Program object in order to call a member method.

With static methods:

public class Program {     public static void Main()     {         System.Console.WriteLine(Program.Foo());     }      public static string Foo()     {         return "Foo";     } } 

Without static methods (in other words, requiring you to instantiate Program):

public class Program {     public static void Main()     {         System.Console.WriteLine(new Program().Foo());     }      public string Foo() // notice this is NOT static anymore     {         return "Foo";     } } 

Main must be static because otherwise you'd have to tell the compiler how to instantiate the Program class, which may or may not be a trivial task.

Answer 2

You can write non static methods too, just you should use like this

static void Main(string[] args) {     Program p = new Program();     p.NonStaticMethod(); } 

The only requirement for C# application is that the executable assembly should have one static main method in any class in the assembly!