排序算法<四>希尔排序

#include<iostream>
using namespace std;
int arr[]={11,12,51,23,64,23,68,1,12};
void shellsort1(int arr[])  {  
  int i, j, gap;  
  for (gap = 9 / 2; gap > 0; gap /= 2) //步长  
    for (i = 0; i < gap; i++)  {       //直接插入排序    
      for (j = i + gap; j < 9; j += gap)   
        if (arr[j] < arr[j - gap]) { 
          int temp = arr[j];  
          int k = j - gap;  
          while (k >= 0 && arr[k] > temp) { 
             arr[k + gap] = arr[k];  
             k -= gap;  
          }  
          arr[k + gap] = temp;  
        }  
    }  
} 
int main() {
  shellsort1(arr);
  for (int i=0; i<9; i++)
    cout<<arr[i]<<" ";
}