C++17 STL Cookbook

How it works...

Regular expressions (or regex in short) are extremely useful. They can look really cryptic, but it is worth learning how they work. A short regex can spare us writing many lines of code if we did the matching manually.

In this recipe, we first instantiated an object of type regex. We fed its constructor with a string that describes a regular expression. A very simple regular expression is ".", which matches every character because a dot is the regex wildcard. If we write "a", then this matches only on the 'a' characters. If we write "ab*", then this means "one a, and zero or arbitrarily many b characters". And so on. Regular expressions are another large topic, and there are great explanations on Wikipedia and other websites ...