Diving into the design process

As introduced earlier, the project design starts with listing general entities, such as users, products, and warehouses when designing an e-commerce platform:

We then decompose each entity into smaller components. To make things clearer, consider each entity as a separate class. When thinking of an entity as a class, it makes more sense in terms of decomposition. For example, we express the user entity as a class:

class User
{
public:
  // constructors and assignment operators are omitted for code brevity
  void set_name(const std::string& name);
  std::string get_name() const;
  void set_email(const std::string&);
  std::string get_email() const;
  // more setters and getters are omitted for code brevity

private:
  std::string name_;
  std::string email_;
  Address address_;
  int age;
};

The class diagram for the User class is the following:

However...