👉🏻 If you want to enjoy the full experience exploring this pdf, check it out here Modern C++ Concepts OOP

C++17, C++20 Features

filesystem library

• introduced in C++17, enhanced in C++20

• Methods and classes in filesystem library:

  • Path class → Represents filesystem paths (filename, directory names)

  #include <iostream>
  #include <filesystem>
  
  using namespace std;
  
  namespace fs = std::filesystem;
  
  int main() {
  	//the generic path
  	filesystem::path p1 = "/home/user";
  	//the specific path
  	fs::path p2 = "documents/file.txt";
  	//the / operator is overloaded in the filesystem library to concatenate paths
  	fs::path full_path = p1 / p2;
  	cout << "Full Path: " << full_path;
  	return 0;
  
  }
  

  • File operations → Functions for creating, removing and checking files and directories

  #include <iostream>
  #include <filesystem>
  #include <fstream>
  
  namespace fs = std::filesystem;
  
  int main() {
  
  	// Create a directory in the current working directory
  	fs::create_directory("new_directory");
  
  	// Create or open a file
  	//The file is immediately closed after creation 
  	//because no operations are performed on it.
  	std::ofstream("new_directory/example.txt");
  
  	// Remove file
  	fs::remove("new_directory/example.txt");
  
  	// Remove directory
  	// To remove a directory, it must be empty
  	//if it contains files or sub directories the operation will fail
  	fs::remove("new_directory");
  
  	return 0;
  }
  

  • Directory Traversal → Operating over directory contents
  • File Metadata → Accessing file properties like size, permissions, etc
  • Exception handling → Includes error reporting using filesystem_error

Structured Binding

• Structured binding is a feature introduced in C++17 that allows unpacking or destructuring of complex objects, such as tuples, pairs, arrays, or user-defined types, into individual variables
• The syntax:

auto[v1, v2, v3, ...] = object;
//the auto keyword automatically deduce the type of the elements
//the object could be a tuple, pair, array, or a custom class

• A tuple is a data structure that groups together multiple values, which can be of different types, into a single compound object

//Unpacking a tuple
#include <tuple>
int main() {
	tuple <int, double, char, string> t = {1, 3.14, 'A', "Hello"};
	//store the values of the tuple into variables
	auto [x, y, z, w] = t;
	//instead of looping, you can just cout the values
	cout << x << " " << y << " " << z << " " << w;
}

C++20 Ranges

• Ranges in C++20 are a powerful feature introduced to simplify working with sequences of elements, such as arrays, vectors, and other containers
• The Ranges library is part of the Standard Library and is found in the <ranges> header