定义一个不受计算机字长限制的整数类INT，要求INT与INT以及INT与C++基本数据类型int之间能进行＋、－、×、÷和＝运算，并且能通过cout输出INT类型的值-Define an integer type INT not limited by computer word length requirements between INT and INT, INT and C++ basic data type int+,-, and = operator, and through cout