September 2017
Intermediate to advanced
822 pages
26h 51m
English
book
C++ Templates: The Complete Guide, 2nd Edition
by David Vandevoorde, Nicolai M. Josuttis, Douglas Gregor
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Chapter 26
Discriminated Unions
The tuples developed in the previous chapter aggregate values of some list of types into a single value, giving them roughly the same functionality as a simple struct. Given this analogy, it is natural to wonder what the corresponding type would be for a union: It would contain a single value, but that value would have a type selected from some set of possible types. For example, a database field might contain an integer, floating-point value, string, or binary blob, but it can only contain a value of one of those types at any given time.
In this chapter, we develop a class template Variant that dynamically stores a value of one of a given set of possible value types, similar to the C++17 standard library’s std::variant<> ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.