已知如下一个递归程序，该程序的目的是输出给定字符的所有排列，请分析该程序的递归过程，然后将其用人工栈进行模拟，也就是将该递归程序转换成非递归程序：-Known as a recursive procedure, the objective of the program is all arranged output given character, please analyze the recursive process of the program, and then the artificia