why do we have using system, using system.collections.Generic, and so on?!

Question

why there are so many "using....." commands are they similar like include<stdio.h> in C

Answer 1

Yep.

Answer 2

yes, those "using"s are similar to include in C and C++.

also similar to "import" in Java.

That "using" keyword is used so that your code will be referenced to the libraries outside your class.

Answer 3

I think what he means is if we call using System, why should we call using System.Generics if Generics is a child class from System. I would understand that by calling System, you will have access to Generics as well, but thats not true, you still need to use System.Generics and so on.