希尔排序

测试方法见另外三篇：快速排序、归并排序、堆排序

代码：

void ShellSort(int * const arr, const DWORD number)//希尔排序
{
    int tmp;
    DWORD i, j;
    DWORD step;
    DWORD index;
    if (number < 2)
    {
        return;
    }
    for (step=number/2; step>0; step/=2)
    {
        for (i=0; i<step; i++)
        {
            for (j=step+i; j<number; j+=step)
            {
                for (index=j; index>=step; index-=step)
                {
                    if (arr[index] < arr[index-step])
                    {
                        tmp = arr[index];
                        arr[index] = arr[index-step];
                        arr[index-step] = tmp;
                    }
                    else
                    {
                        break;
                    }
                }
            }
        }
    }
}