用递归法将一个整数n转换成字符串（例如输入4679，应输出字符串“4679”），n为不确定数，可以是位数不超过5，且数值在-32768~32767之间的任意整数。

-Recursive method to convert a string to an integer n (for example, type 4679, should output the string " 4679" ), n is the number of uncertainty, which can be not more than 5 digits, and the values in an arbitrary-32768 ~ 32767 integer.