The Foo Family
==============

Definition: The Foo Family
--------------------------

.. plantuml::

   @startuml

   interface IFoo {
     + bar()
   }

   class AFoo {
     + bar()
   }
   class BFoo {
     + bar()
   }

   IFoo <|.. AFoo
   IFoo <|.. BFoo

   @enduml

.. literalinclude:: code/the-foos.h
   :language: c++
   :caption: :download:`code/the-foos.h`

Scenario: Polymorphic Access
----------------------------

**Given the following usage:**

.. literalinclude:: code/polymorphic-access.cpp
   :language: c++
   :caption: :download:`code/polymorphic-access.cpp`

**Which of the following statements is true?**

.. list-table::
   :align: left
   :header-rows: 1

   * * Statement
     * True
   * * A call as shown gives the output as shown

       .. code-block:: console

          $ ./program a
          AFoo::bar()
          42
     *

.. list-table::
   :align: left
   :header-rows: 1

   * * Statement
     * True
   * * A call as shown gives the output as shown

       .. code-block:: console

          $ ./program b
	  BFoo::bar()
	  666
     *

.. list-table::
   :align: left
   :header-rows: 1

   * * Statement
     * True
   * * A call as shown will do nothing because ``foo`` is null

       .. code-block:: console

          $ ./program c
	  ...?...
     *

.. list-table::
   :align: left
   :header-rows: 1

   * * Statement
     * True
   * * A call as shown will likely crash because ``foo`` is null

       .. code-block:: console

          $ ./program c
	  ...?...
     *

.. list-table::
   :align: left
   :header-rows: 1

   * * Statement
     * True
   * * However called, the program has a memory leak
     *

Scenario: Undefined Access
--------------------------

**Given the following usage:**

.. literalinclude:: code/undefined-access.cpp
   :language: c++
   :caption: :download:`code/undefined-access.cpp`

**Which of the following statements is true?**

.. list-table::
   :align: left
   :header-rows: 1

   * * Statement
     * True
   * * A call as shown will cause undefined behavior

       .. code-block:: console

          $ ./program a
	  ...?...
     *

.. list-table::
   :align: left
   :header-rows: 1

   * * Statement
     * True
   * * A call as shown will cause undefined behavior

       .. code-block:: console

          $ ./program b
	  ...?...
     *

Scenario: Memory Leak
---------------------

**Given the following usage:**

.. literalinclude:: code/memory-leak.cpp
   :language: c++
   :caption: :download:`code/memory-leak.cpp`

**Which of the following statements is true?**

.. list-table::
   :align: left
   :header-rows: 1

   * * Statement
     * True
   * * A call as shown will cause undefined behavior

       .. code-block:: console

	  $ ./program a
	  ...?...
     *

.. list-table::
   :align: left
   :header-rows: 1

   * * Statement
     * True
   * * A call as shown will leak memory

       .. code-block:: console

	  $ ./program a
	  ...?...
     *