快速排序算法

 1 #include <stdio.h>
 2 
 3 /****************************************************
 4 **function:    print
 5 **description: print the element
 6 **intput:      the array
 7 **return:      void
 8 ****************************************************/
 9 void print(int array[])
10 {
11     int i;
12     
13     for(i = 0; i < 8; i++)
14     {
15         printf("%d ", array[i]);
16     }
17 }
18 /****************************************************
19 **function:    quicksort
20 **description: detach the array into two parts
21 **intput:      the array, low, high
22 **return:      the position of the key
23 ****************************************************/
24 int quicksort(int a[], int low, int high)
25 {
26     int key = a[low];
27 
28     while(low < high)
29     {
30         while(low < high && a[high] >= key) high--;
31         a[low] = a[high];    /* exchange the value*/
32         while(low < high && a[low] < key) low++;
33         a[high] = a[low];    /* exchange the value*/
34     }
35     a[low] = key;             /* the last value*/
36     return low;
37 }
38 /****************************************************
39 **function:    qsort
40 **description: sort the array 
41 **intput:      the array, low, high
42 **return:      void
43 ****************************************************/
44 void qsort(int a[], int low, int high)
45 {
46     int pivot;
47     if (low < high)
48     {
49         pivot = quicksort(a, low, high);
50         qsort(a, low, pivot-1);       /*deal the first part */
51         qsort(a, pivot+1, high);     /*deal the second part */
52     }
53 }
54 /* test the code */
55 void qsorttest(int a[], int low, int high)
56 {
57     qsort(a, low, high);
58     print(a);
59 }
60 
61 int main(int argc, char *argv[])
62 {
63     int array[] = {11, 34, 23, 7, 21, 13, 9, 81};
64     qsorttest(array, 0, 7);
65     return (0);
66 }
67 
68 /**********************end file****************************/