Parse Strings with Regular Expressions
Explore how to parse strings using C++20 regular expressions. Understand regex syntax and iteration with sregex_token_iterator to extract specific text patterns, such as hyperlinks from HTML, enabling efficient lexical analysis and pattern matching in your C++ programs.
We'll cover the following...
Regular Expressions (commonly abbreviated as regex) are commonly used for grep, awk, and sed, and are an integral part of the Perl language. There are a few common variations in the syntax. A POSIX standard was approved in 1992, while other common variations include Perl and ECMAScript (JavaScript) dialects. The C++ regex library defaults to the
The regex library was first introduced to the STL with C++11. It can be very useful for finding patterns in text files.
How to do it
For this recipe, we will extract hyperlinks from an HTML file. A hyperlink is coded in HTML like this:
<a href="http://example.com/file.html">Text goes here</a>
We will use a regex object to extract both the link and the text, as two separate strings.
Our example file ...