求一个数组中的中位数。当数组中数据位奇数时比较好求，而当其位偶数数该如何处理呢。本程序实现了这两种不通情况下的中位数。-Seeking an array median. When the array data bit odd good demand, and when its bit even number of number of how to deal with it. This program implements the median of these two barrier case.