The Entity class represents a unique entity in an Entity-Component-System (ECS) architecture. Entities are identified by a unique ID and are compared based on this ID.

namespace ecs {
    class Entity {
      public:
        Entity(std::size_t id) : _id(id) {}

        std::size_t getId() const
        {
            return _id;
        }

        std::size_t operator=(const std::size_t &id)
        {
            _id = id;
            return id;
        }

        bool operator==(const Entity &other) const
        {
            return _id == other._id;
        }

      private:
        std::size_t _id;
    };
} // namespace ecs

Public Members:

• Constructor:
  • Entity(std::size_t id)
    • Initializes an entity with a unique identifier (ID).
    • Parameters:
      • id: A std::size_t value representing the entity's unique ID.
• std::size_t getId() const
  • Returns the unique identifier (ID) of the entity.
  • Returns:
    • A std::size_t value that represents the entity's ID.
• std::size_t operator=(const std::size_t &id)
  • Assigns a new ID to the entity.
  • Parameters:
    • id: A std::size_t value representing the new ID.
  • Returns:
    • The newly assigned id.
• bool operator==(const Entity &other) const
  • Compares two entities for equality by checking their IDs.
  • Parameters:
    • other: Another Entity object to compare with.
  • Returns:
    • true if the IDs of both entities are the same, otherwise false.

Private Members:

• std::size_t _id
  • A std::size_t variable that stores the unique identifier of the entity.

Supplement:

• Entity Identification:
  • The class revolves around the concept of a unique ID (_id) that identifies each entity in the ECS system. Entities are distinguished and compared based on this ID.
• Comparison:
  • The equality operator (==) allows comparison between two Entity objects. Two entities are considered equal if they have the same ID.
• ID Assignment:
  • The assignment operator allows an entity to be given a new ID after its creation. This operator ensures that an entity’s ID can be dynamically modified.