C++17 STL Cookbook

How to do it...

We will implement a little tool that searches for user-provided text patterns in files. The tool works similar to the UNIX tool grep, but will not be as mature and powerful, for the sake of simplicity.

1. First, we need to include all the necessary headers and declare that we use namespace std and filesystem.

      #include <iostream>      #include <fstream>      #include <regex>      #include <vector>      #include <string>      #include <filesystem>            using namespace std;      using namespace filesystem;

2. We implement a helper function first. It accepts a file path and a regular expression object that describes the pattern we are looking for. Then, we instantiate a vector that shall contain pairs of matching line numbers and their content. And we instantiate ...