插入排序的C语言实现

 1 /*-----------------------------
 2 *
 3 * For    排序算法学习
 4 * IDE    DEV-CPP4.9.2
 5 * Auhtor  Cao
 6 * Date   2012/10/17
 7 *------------------------------
 8 */
 9 #include <stdlib.h>
10 #include <stdio.h>
11 //插入排序
12 void insertSort(int* arr,size_t n)      
13 {
14      
15       int i,j,key;
16       for(i=1;i<n;i++)                      //初始:ar={169,45,2,489,469,4,-778,156}
17       {                                    
18           key = arr[i];                 
19           j=i-1;
20           while(j>=0&&arr[j]>key)          //把key与前面的arr[0~j]进行比较  
21                   arr[j+1] = arr[j--];     //找到一个比key大的数就把它后移 
22           arr[j+1]=key;                    //上面的循环终止，则j+1就key的位置  
23       }  
24       /*
25       *Loop0:169,45,2,489,469,4,-778,156  数组原型  取key=arr[2]=2 
26       *Loop1:2,169,45,489,469,4,-778,156  key=2比arr[1] arr[0]小，找到arr[2]的位置arr[0]->
27       *Lopp3:2,169,45,469,489,4,-778,156  进行插入和ArrayList的insert(value,index)一样 
28       *Loop4:2,169,45,469,489,4,-778,156  .......
29       *Loop5:2,4,169,45,469,489,-778,156  ...
30       *Loop6:-778,2,4,169,45,469,489,156  ...
31       *Loop7:-778,2,4,156,169,45,469,489  ...
32       */
33 } 
34 
35  int main(int argc, char *argv[])
36  {
37      int arr[] = {169,45,2,489,469,4,-778,156};
38      size_t len = (sizeof arr/sizeof arr[0]);
39      insertSort(arr,len);
40      int i;
41      for(i=0;i<len;i++)
42      {
43          printf("%d ,",arr[i]);               
44      }
45      //====>-778,2,4,156,169,45,469,489
46      getchar();
47      return 0;
48  }