Answer Happy

Implement the constructor and compute method
of the Doubler class below. The constructor should set
the the startingVal and n member variables.
The compute method should double
the startingVal exactly n times and return the
result. For example, the code:
should print 48, because 3 doubled once is 6, 3 doubled
twice is 12, 3 doubled 3 times is 24, and so 3 doubled 4 times is
48.