利用通用排序函数实现日期排序

通用排序函数是将各种类型数组的元素进行排序的函数．而日期型数据比较特殊，使用通用排序函数实现日期型数据排序，必须做一些特殊的处理．首先，把日期型数据转变成单个的数，然后把这些数存于数组，利用通用排序函数进行排序，最后将排序后的数组转变成日期输出．

Apply General Sorting Function to Realize Date Sorting

General sorting function is a function to sort elements of different type array. Because data of date type is very particular, it is need to do some manipulations for applying general sorting function to realize date sorting. Firstly, to convert data of date type into single number. Secondly, to save the numbers to a array , to apply general sorting function to sort the array. Lastly , to convert elements of the array into data of date type and to output.