Classes and OOP in C++

#include <iostream>
#include <string>

class User {
private:
    std::string name_;
    int age_;
public:
    // Constructor
    User(std::string name, int age) : name_(std::move(name)), age_(age) {}

    // Destructor (called on scope exit / delete)
    ~User() { /* close files, free resources, etc. */ }

    // Copy constructor + copy assignment (Rule of Three)
    User(const User& other) = default;
    User& operator=(const User& other) = default;

    // Move constructor + move assignment (Rule of Five)
    User(User&& other) noexcept = default;
    User& operator=(User&& other) noexcept = default;

    // Member functions (const = doesn't modify *this)
    const std::string& name() const { return name_; }
    int age() const { return age_; }
    void birthday() { ++age_; }
};

int main() {
    User alex("Alex", 30);
    alex.birthday();
    std::cout << alex.name() << " is now " << alex.age() << "\n";
}