Name
qsort function — Sorts an array
Synopsis
extern "C" void qsort(void* base, size_t count, size_t size, int (*compare)(const void*, const void*)) extern "C++" void qsort(void* base, size_t count, size_t size, int (*compare)(const void*, const void*))
The qsort
function sorts in
ascending order an array of count
elements, each of size size
bytes, in which base
is the
pointer to the first element. The array must have POD type. The sort
is not stable, that is, the relative order of identical elements is
not necessarily preserved.
The compare
function takes
two pointers into the array and compares the elements. It returns an
integer: negative if the first element is less than the second,
positive if the first is greater than the second, or 0
if the two elements are equal.
The name qsort
derives from
the original implementation, which used the Quick Sort algorithm.
The current standard does not specify which sort algorithm is used,
nor does it specify any performance characteristics of the sort
algorithm.
Two versions of qsort
are
declared so the compare
function
can have "C
" linkage or "C++
" linkage.
See Also
bsearch function,
sort
in <algorithm>
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