howManyBooks:
  Given inputs of initial price, discount, floor price and budget it should return the number of books that can be purchased along with any remaining money after the purchase.


How to use:
  1. compile the program:
    (Make sure you are inside the "src" folder)
    javac com/tokbox/interview/Solution.java

  2. run the program:
    (Make sure you are inside the "src" folder)
    java com.tokbox.interview.Solution

  3. (while the program is running):
     "test": will run pre-defined unit tests
     "exit": will exit the program
     "<initialPrice> <discount> <floorPrice> <budget>": will calculate the number of book purchased, and remaining money
        e.g.: sample input: 50 4 25 300
        sample output:
            input: initialPrice=50 discount=4 floorPrice=25 budget=300
            Purchasing Result: book=8, remaining=9