Assume the integers to be multiplied
are unsigned and non-negative.
You are to use the standard BigInteger package in java.
You may use any method found in java.math.BigInteger,
except its "multiply", "divide" and "reciprocal" methods.
In particular, you
may use its "add", "subtract", "ShiftRight", "ShiftLeft"
and "bitLength" methods.
Other useful methods include "equals" and "compareTo".
For instance, do not say
if (myNum == yourNum) {...}
This just compares the "references" to these BigIntegers!
Do instead:
if (myNum.equals(yourNum)) {...}
For more general comparisons, use "compareTo".
Useful constants: "ZERO" and "ONE".
They are static, so to
access these constants, use (e.g.) "BigInteger.ZERO".