qsort()

Syntax

  #include <stdlib.h>

  void *qsort(const void *array, size_t n,

              size_t size, cmp_func cmp);

Description

qsort() sorts the array according to the ordering implemented by the comparison function. It calls the cmp() comparison function with two pointers to array elements ( *key, *other). Thus, the type cmp_func() can be declared as:

  typedef int (*cmp_func)(const void *key,

   const void *other);

The comparison function returns an integer according to the following table.

Table 1. cmp_func() Return Value
`*key` Element Value	Return Value
Less than `*other`	Less than zero (negative)
Equal to `*other`	Zero
Greater than `*other`	Greater than zero (positive)

The arguments to qsort() are listed in the following table.

Table 2. Possible Arguments for qsort() Function
Argument Name	Meaning
`array`	A pointer to the beginning (the first element) of the array to be sorted
`n`	The number of elements in the array
`size`	The size (in bytes) of one element in the table
`cmp()`	The comparison function

Note: Make sure the array contains elements of the same size.

Return

See also