Powers of 2

File PowersOf2.java contains a skeleton of a program to
read in an integer from the user and print out that many
powers of 2, starting with 20.

  1. Using the comments as a guide, complete the program
     so that it prints out the number of powers of 2 that
     the user requests. Do not use Math.pow to compute 
     the powers of 2! Instead, compute each power from
     the previous one (how do you get 2n from 2n-1?).
     For example, if the user enters 4, your program should 
     print this:

     Here are the first 4 powers of 2:
     1
     2
     4
     8

  2. Modify the program so that instead of just printing
     the powers, you print which power each is, e.g.:

     Here are the first 4 powers of 2:
     2^0 = 1
     2^1 = 2
     2^2 = 4
     2^3 = 8