C++ Primer, Fifth Edition

10.1. Overview

Most of the algorithms are defined in the algorithm header. The library also defines a set of generic numeric algorithms that are defined in the numeric header.

In general, the algorithms do not work directly on a container. Instead, they operate by traversing a range of elements bounded by two iterators (§ 9.2.1, p. 331). Typically, as the algorithm traverses the range, it does something with each element. For example, suppose we have a vector of ints and we want to know if that vector holds a particular value. The easiest way to answer this question is to call the library find algorithm:

int val = 42; // value we'll look for ...