C++ Library Catalog

1. Design the Book class

Define a Book class with a constructor, destructor, and core fields.

• Book has at minimum title, author, ISBN, and a checked-out boolean
• The constructor initializes every field; the destructor is defined even if trivial

2. Store and query the catalog

Use std::vector<Book> plus <algorithm> functions (find_if, sort) to search and sort it.

• A find-by-title function uses std::find_if rather than a hand-written loop
• The catalog can be sorted by title or author using std::sort with a comparator

3. Introduce a smart pointer

Use std::unique_ptr or std::shared_ptr somewhere ownership genuinely needs it.

• The smart pointer's ownership rationale is explained (why unique_ptr vs shared_ptr was chosen)
• No raw new/delete is used for that resource

4. Add a derived class with polymorphism

Model an EBook or ReferenceBook subclass overriding a virtual function from Book.

• The base class declares at least one virtual function (e.g. describe())
• The derived class overrides it, and calling it through a Book* or Book& dispatches to the derived version