一个基于c#的大整数类，内含各种大整数的操作

一个自己写的 C# BigInteger 类，.net 类库中没有 BigInteger 类，写此类是为了与 java 中的 BigInteger 对应，以方便大数运算-One wrote it myself C# BigInteger Class,. Net library does not BigInteger class, write these in order to correspond with the java in the BigInteger to facilitate the