Features of the standard algorithms

To get a better understanding of the standard algorithms, it's good to know a bit about the features and common patterns used by all algorithms in the <algorithm> header. As already stated, the algorithms under the std and std::ranges namespaces have a lot in common. We will start here with the general principles that are true for both the std algorithms and the constrained algorithms under std::range. Then, in the next section, we will move on to discuss the features that are specific to the constrained algorithms found under std::ranges.

Algorithms do not change the size of the container

Functions from <algorithm> can only modify the elements in a specified range; elements are never added or deleted from the underlying container. Therefore, these functions never alter the size of the container that they operate on.

For example, std::remove() or std::unique() do not actually remove elements from a container (despite...