Finding items in ordered and unordered vectors

Often, we need to tell if some kind of item exists within some range. And if it does, we often also need to modify it or to access other data associated with it.

There are different strategies for finding items. If the items are present in a sorted order, then we can do a binary search, which is faster than linearly going through the items one by one. If it is not sorted, we are stuck with linear traversal again.

The typical STL search algorithms can do both for us, so it's good to know them and their characteristics. This section is about the simple linear search algorithm std::find, the binary search version std::equal_range, and their variants.

How to do it...

In this section, we are going to use linear and binary search algorithms on a small example data set:

1. We first include all the necessary headers and declare that we use the std namespace:

      #include <iostream>
      #include <vector>
      #include <list>
      #include...