1 #include <stdlib.h> 2 #include <stdio.h> 3  4 #define ARRAY_SIZE 10 5  6 void swap(int *x, int *y) 7 { 8     int a = *x; 9     *x = *y;10     *y = a;11 }12 13 int randint(int low, int high)14 {15     return (low + (rand() % (high - low + 1)));16 }17 18 void quicksort(int *arr, int low, int high)19 { 20     int i, mid;21     if (low >= high) 22         return;23     swap(arr+low, arr + randint(low, high));24     mid = low;25     for (i = low+1; i <= high; i++)26     {27         if (arr[i] < arr[low])28         {29             swap(arr + ++mid, arr + i);30         }31     }32     swap(arr + low, arr + mid);33     quicksort(arr, low, mid-1);34     quicksort(arr, mid+1, high);35 }36 37 void printArray(int *arr, int size, const char *prefix)38 {39     printf("%s:", prefix);40     for(int i = 0; i < size - 1; i++)41     {42         printf("%d ", arr[i]);43     }44     printf("\n");45 }46 47 int main(int argc, char **argv)48 {49     int array_unsort[ARRAY_SIZE] = {11, 23, 44, 55, 32, 12, 8, 9, 63, 82};50     printArray(array_unsort, ARRAY_SIZE, "before sort");51     quicksort(array_unsort, 0, ARRAY_SIZE-1);52     printArray(array_unsort, ARRAY_SIZE, "after sort");53     return 0;54 55 }