将整数的各个数位存储为一个长度为四十的字符数组中各个元素。能够进行四十位的整数的加减法-Create a class HugeInteger that uses a 40-element array of digits to store integers as large as 40 digits each (e.g. 8783 is stored as an array of {3,8,7,8,0,0,0,....} ), and use another boolean membe