This is my attempt to imitate the working of Big Integer library in java.

The input will be a large number in form of a string that will be in base 10.
I am essentially converting this number into a very large base number and storing it in an array. After that, the problem boils down to operations on 2 arrays. I have also included various kinds of evaluations as well, like postfix and infix.

TestNum.java is used to test the Num.java file, I have tested my program by processing very large inputs like calculating 50,000th fibonacci number and calculating 999,999th power of 3.

Please refer to the code for details of implementation.