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Topic 4 - Functions and Structured Programming
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- 
   A *function* is a portion of a program which can be called to
   perform a task and then return to the calling program.

- We have already seen some functions provided by the system (:ref:`printf`,
  :ref:`scanf`, *sqrt* (see :ref:`cmath`) ...) and we talked briefly about
  how to write our own functions. (see :ref:`functions_intro`)

- 
   In this topic we will discuss the following details about
   functions:

   
   #. Review of how to write and call functions.

   #.
      Rules related to the scope of variables used with functions. This
      leads directly into the general subject of data storage classes and
      a related, but side topic of how data and memory is managed by the
      computer.

   #.
      Program design issues as related to splitting up the program's work
      into functions.

   #. Recursive functions and program design using recursion.

**Contents**

.. toctree::
   :maxdepth: 2

   functions
   assert
   call_value
   scope
   storage_class
   prog_design
   recursion