In the ERRATA section, there is the following update/comment:

Question 2 states:
You need to make a logical comparison where two values must return true in order for your code to execute the correct statement. Which logical operator enables you to achieve this?

Answer given: "D. &&"

However, both answers "D. &&" and "C. &" are correct.

I disagree with this. The question asks for the logical operator, which is &&. The & is a bitwise operator, not a logical operator, that operates on integers.

It may happen that & will act the same way as && in the question that was asked, but it would be very bad practice in the real world to use & when you are doing logical tests.

So I agree with the book that the correct answer is D, and NOT D and C as stated in the errata comment,.

I think the Errata correction is right. & is a bitwise operator, but it is also a logical operator (i.e. its use is overloaded, like say + with ints and strings).

The difference between the two is that & will always evaluate both sides of the expression, whereas && will only evaluate the left side first and if it is false will not evaluate the right hand side.

Personally I have not used the & version, but use && regularly, e.g.
if (myObject != null && myObject.IsValid)

Using & in the above example would result in a NullReferenceException if myObject was null.

I would agree that D is the better answer though.

I am having issues creating a NEW THREAD on this forum. Are we no longer allowed to create new threads to this particular forum?

I am having the same problem, I sent an e-mail but have heard nothing back