qsort
From cppreference.com
Defined in header
<stdlib.h>
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Sorts the given array pointed to by ptr
in ascending order. The array contains count
elements of size
bytes. Function pointed to by comp
is used for object comparison.
If comp
indicates two elements as equivalent, their order is undefined.
Contents |
[edit] Parameters
ptr | - | pointer to the array to sort |
count | - | number of element in the array |
size | - | size of each element in the array in bytes |
comp | - | comparison function which returns a negative integer value if the first argument is less than the second, a positive integer value if the first argument is greater than the second and zero if the arguments are equal. int cmp(const void *a, const void *b); The function must not modify the objects passed to it. |
[edit] Return value
(none)
[edit] Example
The following code sorts an array of integers using qsort()
Run this code
#include <stdio.h> #include <stdlib.h> int compare_ints(const void* a, const void* b) { const int *arg1 = a; const int *arg2 = b; return *arg1 - *arg2; } int main(void) { int i; int ints[] = { -2, 99, 0, -743, 2, 3, 4 }; int size = sizeof ints / sizeof *ints; qsort(ints, size, sizeof(int), compare_ints); for (i = 0; i < size; i++) { printf("%d ", ints[i]); } printf("\n"); return EXIT_SUCCESS; }
Output:
-743 -2 0 2 3 4 99
[edit] See also
searches an array for an element of unspecified type (function) |
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C++ documentation for qsort
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