Professional C++, 5th Edition

26Advanced Templates

WHAT'S IN THIS CHAPTER?

• The different kinds of template parameters
• How to use partial specialization
• How to write recursive templates
• What variadic templates are
• How to write type-safe variable argument functions using variadic templates
• What constexpr if statements are
• How to use fold expressions
• What metaprogramming is and how to use it
• What type traits can be used for

WILEY.COM DOWNLOADS FOR THIS CHAPTER

Please note that all the code examples for this chapter are available as part of this chapter's code download on the book's website at www.wiley.com/go/proc++5e on the Download Code tab.

Chapter 12, “Writing Generic Code with Templates,” covers the most widely used features of class and function templates. If you are interested in only a basic knowledge of templates so that you can better understand how the Standard Library works, or perhaps write your own simple class and function templates, you can skip this chapter on advanced templates. However, if templates interest you and you want to uncover their full power, continue reading this chapter to learn about some of the more obscure, but fascinating, details.

MORE ABOUT TEMPLATE PARAMETERS

There are actually three kinds of template parameters: type, non-type, and template template (no, you're not seeing double: that really is the name). So far, you've seen examples of type and non-type parameters (in Chapter 12), but not template template parameters. There are also some tricky aspects ...