C equivalent to Arrays.sort from Java - qsort? (How do i find the nature of its implementation)

Question

Hi All,

I'm fairly new to the C programming language but I know that it is not standardized in the same way as Java.

When performing a comparisson of the runtime of a algorithm, to keep the analysis fair, I need to call a method similar to Java's Array.sort(int []).

void qsort(void *base, size_t nmemb, size_t size, int (*compar)(const void *, const void *));

Seems to be my best bet but I was wondering how I could find out the backend implementation for the version of C that I'm compiling to.

How can I find out which implementation I am using? Does this depend on the Compiler or the includes? I am running I run Ubuntu and use the gcc compiler, all of my tools are obtained through the synaptic package manager or are installed by default.

I hope this question makes sense!

Kind regards,

Gavin

Answer 1

Hi,

qsort is part of the C stadard library, so a look at the libc code might help: http://www.google.com/codesearch/p?hl=en#XAzRy8oK4zA/libc/stdlib/qsort.c&q=qsort

Hope this helps, Vlad

Answer 2

qsort is a C standard library function.

Answer 3

Run

man qsort

It gives the description of what qsort is doing. When you need to find out the information about a C function XXX, try to do man XXX first. Then, if there's not enough info, search for XXX on Google.

Answer 4

I'm fairly new to the C programming language but I know that it is not standardized in the same way as Java.

On the contrary, C is heavily standardised. There has been an ANSI/ISO standard for C since 1989.

Answer 5

What implementation you get depends on the libc you use. But you don't have to care about this too much, they all should behave the same.

Answer 6

Paul Hsieh present a very fast quicksort in a sorting comparation
Numerical Recipes in C has a excelent quicksort