用C语言言实现希尔排序。希尔排序(Shell Sort)是插入排序的一种。也称缩小增量排序，是直接插入排序算法的一种更高效的改进版本。(Using C language to achieve Hill sort.The Hill sort (Shell Sort) is a sort of insertion sort. Also called reduced delta sort is a more efficient version of the sorting algorithm directly inserted.)