A ________ is a pattern composed of a sequence of characters that describe allowable input variants.

Which of the following is NOT an accurate Google+ statistic?

A) Indications are that Google+ users tend to be more technically savvy than users of other social networks. B) Facebook has a 43:57 male to female ratio, and Google+ is even more female-oriented, with a 71:29 ratio. C) The Google+ audience is also younger as compared to Facebook, with 39 percent under the age of 34. D) As of September 2012, less than a year after its launch, Google+ claimed more than 400 million users, 100 million of whom were active on a monthly basis.

Abstract classes do not necessarily have:

a. A 0 pointer in their vtable. b. A virtual function prototype with the notation = 0. c. Zero instances of their class. d. Zero references to their class.