This creates a nicely formatted markdown file from all the C++ source code (.cpp and .h) in a given project with multiple subprojects.

create_markdown_from_files.cpp

#include <iostream>
#include <fstream>
#include <filesystem>
#include <string>

namespace fs = std::filesystem;

int main() {
	std::ofstream out("./cpp_snippets.md");
	std::string current = "";
	for (auto& p : fs::recursive_directory_iterator("../")) {
		if (p.is_regular_file() && 
			p.path().parent_path().string().length() >= 13 && 
			(p.path().extension() == ".cpp" || p.path().extension() == ".h")) 
		{
			std::string header = p.path().parent_path().string().substr(13);
			if (current == header) {
				header = "";
			}
			else {
				current = header;
				header = "## " + header;
			}
			std::ifstream in(p.path());
			out << std::endl << header << std::endl << std::endl
				<< "### " << p.path().filename() << std::endl << std::endl;
			std::string line;
			while (getline(in, line)) {
				out << "    " << line << std::endl;
			}
		}
	}

	return 0;
}