Modern C++ Features: From C++11 Revolution to C++20/C++23 Powerhouse

Modern C++ (referring collectively to ISO standards C++11 through C++23) completely revitalized the language. It replaced manual, error-prone C patterns with zero-cost, type-safe abstractions.

Figure 14: Modern C++ Evolution Timeline & Key Standard Capabilities

1. std::optional<T> (C++17)

#include <iostream>
#include <optional>
#include <string>

// Returns an optional value: Either a valid string or empty (std::nullopt)
std::optional<std::string> findUserById(int id) {
    if (id == 101) return "Veewom Admin";
    return std::nullopt; // No user found
}

int main() {
    auto user = findUserById(101);
    if (user.has_value()) {
        std::cout << "Found: " << user.value() << "\n";
    }

    // Default fallback value using value_or():
    std::cout << "Result: " << findUserById(999).value_or("Guest User") << "\n";
    return 0;
}

2. std::filesystem (C++17)

#include <iostream>
#include <filesystem>

namespace fs = std::filesystem;

int main() {
    fs::path myDir = "test_folder";
    if (!fs::exists(myDir)) {
        fs::create_directory(myDir);
        std::cout << "Created directory: " << myDir << "\n";
    }
    return 0;
}