Advanced C Programming

Spring 2022 ECE 264 :: Purdue University

⚠ This is a PAST SEMESTER (Spring 2022).
Due 4/7

qsort

Goals

The goals of this assignment are as follows:
  1. Learn to use function addresses (function pointers).
  2. Learn to use the qsort(…) function.
  3. Gain some perspective on different sorting algorithms.

Overview

This homework is about sorting. For the more practical approach, you will also write a wrapper function for the standard qsort(…) function, an implementation of the quicksort algorithm.

There is one starter file: sorts.h. To get it, run 264get ec01

Outline of a solution

👌 Okay to copy/adapt anything you see in these two screenshot images. (You may not copy code from lecture or anywhere else.)

Demonstration

Reminder: Do not copy this code or anything else into your code (unless marked as "Okay to copy/adapt" by one of the instructors). However, you may run this in your account by running 264get EC01.

Output


Before quick_sort_array(array2)
5 4 2 1 7 6 3

After  quick_sort_array(array2)
1 2 3 4 5 6 7

Requirements

  1. Your submission must contain each of the following files, as specified:
    2. file contents
    sorts.c function definitions
    quick sort array(int✶ array, size t size)
    → return type: void
    Sort array using the qsort(…) standard library function.
    • This should simply call the qsort(…) library function.
    • The qsort(…) function requires the use of function addresses (function pointers).
    • This may not result in any heap allocation (i.e., calls to malloc(…)) by your code.
    • Yes, this is easy, but make sure you understand how it works!
    test_sorts.c function definitions
    main(int argc, char✶ argv[])
    → return type: int
    Test your functions in sorts.c.
    • This must cause every line of code in your sorts.c to be executed.
    • Every public function in sorts.c must be called directly from main(…) and/or from a helper within test_sorts.c.
  2. Only the following externally defined functions and constants are allowed in your .c files. (You may put the corresponding #include <…> statements in the .c file or in your sorts.h, at your option.)
    header functions/symbols allowed in…
    stdbool.h bool, true, false sorts.c, sorts.h, test_sorts.c
    assert.h assert sorts.c, test_sorts.c
    stdio.h printf, fprintf, stdout, FILE test_sorts.c
    stdlib.h malloc, free, NULL, size_t, EXIT_SUCCESS, EXIT_FAILURE sorts.c, test_sorts.c, sorts.h
    Feel free to suggest additional header files or functions that you would like to use.
  3. Submissions must meet the code quality standards and the policies on homework and academic integrity.

Submit

To submit EC01 from within your ec01 directory, type 264submit EC01 sorts.h sorts.c test_sorts.c expected.txt miniunit.h clog.h Makefile

Pre-tester ●

The pre-tester for EC01 has not yet been released. As soon as it is ready, this note will be changed.

Q&A

  1. Can I add helper functions to sorts.c?
    Yes. Make sure the names begin with "_". Also, they should be declared as static.
  2. Is it a violation of the spec if qsort(…) calls malloc(…)?
    No. The only requirement is that your code not call malloc(…) as a result of calling quick_sort_array(…).

Updates

4/4/2022
  • size_t is allowed.