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

     .
4. 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).
5. Capacity Constraint: The bag capacity is fixed at 20.
6. PlainBag Logic:
   • Use a

     vector<T>

     for storage.
   • Implement standard container behavior for all methods.
7. 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