5. Algorithms

I noted at the beginning of Chapter 1 that containers get the lion’s share of the STL acclaim. In a sense, that’s understandable. The containers are remarkable accomplishments, and they make life easier for legions of C++ programmers on a daily basis. Still, the STL algorithms are significant in their own right, equally capable of lightening a developer’s burden. In fact, given that there are over 100 algorithms, it’s easy to argue that they offer programmers a more finely honed tool set than the containers (a mere eight strong) could ever hope to match. Perhaps their number is part of the problem. Making sense of eight distinct container types is surely less work than remembering 70 algorithm names and trying to keep track of which does what.

I have two primary goals in this chapter. First, I want to introduce you to some lesser-known algorithms by showing you how they can make your life easier. Rest assured that I’m not going to punish you with lists of names to memorize. The algorithms I show you are in this chapter because they solve common problems, like performing case-insensitive string comparisons, efficiently finding the n most desirable objects in a container, summarizing the characteristics of all the objects in a range, and implementing the behavior of copy_if (an algorithm from the original HP STL that was dropped during standardization).