c# - Why is this an incorrect usage of a namespace? -

i'm learning c#, i'm not quite sure namespaces. know leave off "using" statements, , system.console.writeline, or "using system" , "console.writeline", not understand why following doesn't work.

using system.console;  namespace helloworld {     public class program     {         public static void main(string[] args)         {             writeline("hello world");         }     } } 

console not namespace, class. writeline static method of class (so don't need instance use it). in fact, console class appears static (so there no instances).

you cannot using class in c# 5.0 , earlier. according msdn article (http://msdn.microsoft.com/en-us/magazine/dn683793.aspx) can static classes in c# 6.0 (the code wrote compile , work).

msdn console class.