======================
 Assignment 2: mysort
======================

:Date: February 1st 2017
:Deadline: February 22nd 2017 23:59

Objectives
==========

You must implement a list API and a multi-tool number sorting program.

Requirements
============

Your sorting program must be named ``mysort`` and its basic operation is as follows:

- it reads input numbers from its standard input;
- it prints the same numbers in sorted order on its standard output,
  one number per line.

Numbers in the input are separated by white space. Your program must
perform sorting by maintaining a sorted list in memory and maintaining
this order while reading the input (insertion sort).

You must submit your work as a tarball [#]_. Next to the source code,
your archive must contain a text file file named “``AUTHORS``”
containing your name and Student ID.

.. [#] http://lmgtfy.com/?q=how+to+make+a+tarball

Getting started
===============

1. Unpack the provided source code archive; then run ``make``.

2. Try out the generated ``mysort`` and familiarize yourself with its
   interface.

3. Read the file ``list.h`` and understand the interface.

4. Implement the data structure in ``list.c``.

5. Implement the input and insertion sort algorithm in
   ``main.c``.

   You can use e.g. ``du ~ | awk '{print $1}' | ./mysort`` to test your
   work.

Grading
=======

Your grade starts from 0, and the following tests determine your grade:

- +0,5pt if you have submitted an archive in the right format with an ``AUTHORS`` file.
- +0,5pt if your source code builds without errors and you have modified ``list.c`` or ``main.c`` in any way.
- +2pt if your list API processes insertions and removals properly.
- +3pt if your ``mysort`` processes and sorts its input properly and terminates with exit code 0.
- -0,5pt if your program misbehaves on zero-sized inputs.
- -0,5pt if your program misbehaves when the last line does not terminate with a newline character.
- -1pt if ``valgrind`` reports errors while running your program.
  Valgrind and the address sanitizer don't play well together so
  temporarily remove the ``-fsanitize=address`` flags from the Makefile when
  testing your code with ``valgrind``.
- -1pt if ``clang -W -Wall`` reports warnings when compiling your code.

The following extra features will be tested to obtain higher grades,
but only if you have obtained a minimum of 5 points on the list above already:

- +1pt if your ``mysort`` accepts option ``-u`` which causes it to eliminate duplicate output lines.
- +0,5pt if your ``mysort`` accepts option ``-S`` which calculates the
  sum of all the items and appends that to the end of the list.
- +0,5pt if your ``mysort`` accepts option ``-s`` taking a single argument, which causes it to only consider input lines multiple of that number.
- +0,5pt if your ``mysort`` accepts option ``-x`` taking a single argument, which causes it to ignore any input line that are multiple of that number.
- +0,5pt if your ``mysort`` accepts option ``-h`` taking a single positive number *N* as argument, which causes it to stop
  after outputting the first *N* lines in sorted order.
- +0,5pt if your ``mysort`` accepts option ``-t`` taking a single positive number *N* as argument, which causes it to stop
  after outputting the last *N* lines in sorted order.
- +0,5pt if your ``mysort`` accepts option ``-3`` which causes it to replace all
  occurrences of the numbers 51, 69 and 42 by 666.

See also
========

- Insertion sort: https://en.wikipedia.org/wiki/Insertion_sort

- Parsing program options using ``getopt``: https://www.gnu.org/software/libc/manual/html_node/Getopt.html