Protected variable will be accessed in inherited class, but 
instance variable of class cant access protected variable.

While friend variable will be accessed in inherited class 
as well as instance variable of class across the project.

Where we need both functionality we are using protected 
friend scope.

friend------access is limited to the current assembly
(application)
protected friend----access is limited to the current 
assembly and types derived from the containing class..

Protected --> Accessible ONLY by 1.Derived classes 2.Within 
the same class

Friend --> Accessible ONLY by 1.Derived classes 2.Classes 
in the same assembly 3.Within the same class

Protected Friend --> Accessible ONLY by 1.Derived classes 
2.Classes in the same assembly 3.Within the same class


This is a very strange prob for which I've been looking for 
an answer for a long time. As you can see above Friend and 
Protected Friend are exactly same simply because 'Friend' 
encompasses the accessibilities of both Protected and 
Protected Friend. The question here is  why did Microsoft 
publish a 'Protected Friend' keyword when it is EXACTLY 
same as Friend.

Friends can be accessed by all classes within assembely but 
not from outside the assembely.

Protected variables can be used within the class as well as 
the classes that inherites this class.

The Protected Friend can be accessed by Members of the 
Assembely (Friend) or the inheriting Assembely class 
(Protected).

So Friend is not same as Protected Friend

I guess the difference is this:
Friend can be accessed by
1. Code within the class
2. Code in derived classes within the same assembly
3. Other code in the same assembly

Protected can be accessed by
1. Code within the class
2. Code in derived classes within the same assemblies
3. Code in derived classes in other assemblies

Protected Friend can be accessed by
1. Code within the class
2. Code in derived classes within the same assembly
3. Other code in the same assembly
4. Code in derived classes in other assemblies