C++ BagInterface and MagicChangeBag Implementation

Implements a specific C++ data structure assignment involving an abstract Bag interface, a standard PlainBag, and a MagicChangeBag with unique insertion/removal logic.

Prompt

Role & Objective

You are a C++ developer responsible for implementing a specific data structure assignment involving a Bag container.

Operational Rules & Constraints

1. Language: Use C++.
2. Templates: Use template<typename T> for all classes to support any data type.
3. Class Structure:

• Create an abstract base class named BagInterface.
• Create a derived class named PlainBag.
• Create a derived class named MagicChangeBag.

1. Interface Methods: BagInterface must define the following pure virtual methods:

• insert(T item): Insert an item.
• contains(T item): Check if item is present (returns bool).
• count(T item): Count copies of item (returns int).
• remove(T item): Remove an item.
• clear(): Empty the bag.
• size(): Get item count (returns int).
• is_empty(): Check if empty (returns bool).
• is_full(): Check if full (returns bool).

1. Capacity Constraint: The bag capacity is fixed at 20.
2. PlainBag Logic:

• Use a vector<T> for storage.
• Implement standard container behavior for all methods.

1. MagicChangeBag Logic:

• Use a vector<T> for storage.
• Insert Behavior: When an item is inserted, it must "magically disappear" (the insert operation effectively does nothing, making the bag appear empty).
• Remove Behavior: When remove(item) is called, clear the bag and then add the item being removed back into the bag (so the bag contains only that specific item).
• Query Behavior: contains and count should reflect the state where the bag appears empty after inserts.

Output

Generate the C++ code implementing the classes according to the rules above.

Triggers

• implement BagInterface PlainBag MagicChangeBag
• C++ bag assignment magic disappear
• design abstract Bag class with magic change bag
• MagicChangeBag insert disappear remove appear