This program calculates the amount of points a customer is rewarded for every dollar above two certain purchase amount (dollars) thresholds.
- Java SDK
In order to write and run a Java program you need to install a Java Software Development Kit, or Java SDK.
You can download a Java SDK for your choice OS at (https://www.oracle.com/java/technologies/javase-downloads.html) - Text Editor or IDE
Atom
Sublime Text
Visual Studio Code
- Windows/Linux
git clone https://github.com/ZTatman/RewardPoints.gitcd RewardPointsjavac RewardsPoints.javajava RewardsPoints < yourInputFile.in
For each case my program will create a customer, randomly generate purchases given a number and a purchase limit, display a customers entire purchase history, calculates the points rewarded for every purchase, and displays the total sum of points rewarded to a customer within a range of months in a customers purchase history.
A customer receives 2 points for every dollar spent over $100 in each transaction, plus 1 point for every dollar spent over $50 in each transaction (e.g. a $120 purchase = 2x$20 + 1x$50 = 90 points). Given a record of every transaction during a three month period, calculate the reward points earned for each customer per month and total. Make up a data set to best demonstrate your solution.
In order to solve this problem I tried to break the problem down into the basic necessary pieces that I needed to construct a solution:
- A function to generate a random collection of purchases
- A way to link a collection of purchases to a certain month and store them as a history
- The lowest purchase amount for which single points can be rewarded for is $50
- The highest purchase amount for which double points can be rewarded for is $100
- A function to calculate the number of points rewarded for each purchase based on the dollar amount
One of the critical design decisions I made was making an object oriented solution. While I did not do this in my code, I wanted to encapsulate every customers purchase history and all customer methods, members, and attributes in a Customer object instantiated from a Customer class. This way, if I ever needed to store as many customers as I wanted in a data structure of my choice. The benefit to this is also that each customer's purchase history is confined to an object and seperate from every other customer's purchase history.
Originally I was using command line arguments when creating the most basic functions. At first it worked just fine and I didnt have to pass in many parameters to the java program. However, as I created more functions and tried to create my own data for this problem, I realized that I had to pretty much put in place my own constraints for this problem and how to solve it. This meant that I started required an increasing number of initial parameters for each case I tested my solution with. Instead of typing all these parameters as command line arguments, I chose to put all these arguments for each case in an input file to be read by my program.
In my program, every customer object has a purchase history. At first I decided to use a Linked List just becuase when I thought of a record I thought of it as a record where each month points to the next month's payment history and each . It was totally possible to create a custom linked list class from scratch and have each node have a month identifier and a list for purchases. Even though this would ensure the insertion order of months, I realized that Insertion and Lookup operations for each month would be O(N) in the worst cases. This would also be true on average if I wanted to add additional purchases to an already existing month or even delete a month's purchase history for a customer.
Instead, I decided to use a LinkedHashMap that is one of several of Java's Collections. LinkedHashMap is like a HashMap except it preserves the order of inserted elements. It also made more sense to use a HashMap<K,V> where each key is the month I want to map to and each value would be an ArrayList of integers that stored a dynamic array of purcahses. In comparison to a Linked List, Insertion and LookUp operations are both O(1) on average and O(log(n)) in the worst case for HashMap Collisions.
This program uses an input file to read in certain parameters on a case by case basis. Every line of the input file contains certain definable parameters.
Every case in the input file follows the following format:
n
name
randPurchaseLimit upperLimit lowerLimit
numMonths
numPurchases month
.
.
.
monthFrom monthTo
Where,
n is the number of cases to look at
name is the first name of a customer
randPurchaseLimit is the upper limit for which a random dollar amount between [0,upperLimit) will be generated
upperLimit is dollare amount for which double points for every dollar above this amount is rewarded
lowerLimit is dollare amount for which single points for every dollar above this amount is rewarded, after double points have been rewarded (if applicable)
numMonths is the number of months for which collections of purchases will be randomly generated
numPurchases is the number of random purchases to generate for a specific month
month is the name of the month for which random purchases will be generated, First letter must be capitalized
monthFrom is the starting month of a range for which a total sum of rewards points will be calculated
monthTo is the ending month of a range for which a total sum of rewards points will be calculated
1
John
500 100 50
5
5 March
12 August
3 September
31 October
0 November
March September
CASE #1: John
-- JOHN's PURCHASE HISTORY --
-- March --
Purchase: $118
Purchase: $454
Purchase: $224
Purchase: $103
Purchase: $481
--------------
-- August --
Purchase: $301
Purchase: $149
Purchase: $135
Purchase: $263
Purchase: $264
Purchase: $95
Purchase: $383
Purchase: $292
Purchase: $56
Purchase: $164
Purchase: $17
Purchase: $325
--------------
-- September --
Purchase: $220
Purchase: $279
Purchase: $308
--------------
-- October --
Purchase: $454
Purchase: $357
Purchase: $207
Purchase: $412
Purchase: $353
Purchase: $115
Purchase: $178
Purchase: $1
Purchase: $354
Purchase: $206
Purchase: $390
Purchase: $496
Purchase: $84
Purchase: $362
Purchase: $1
Purchase: $237
Purchase: $286
Purchase: $315
Purchase: $377
Purchase: $191
Purchase: $247
Purchase: $148
Purchase: $389
Purchase: $222
Purchase: $378
Purchase: $477
Purchase: $165
Purchase: $255
Purchase: $71
Purchase: $114
Purchase: $426
--------------
-- November --
No purchases...
--------------
----- POINTS: MARCH - SEPTEMBER -----
------------- March -------------
Purchase: $118, points: 86
Purchase: $454, points: 758
Purchase: $224, points: 298
Purchase: $103, points: 56
Purchase: $481, points: 812
Monthly points: 2010
------------------------------------
----- April ------
No purchases...
Monthly points: 0
------------------
----- May ------
No purchases...
Monthly points: 0
------------------
----- June ------
No purchases...
Monthly points: 0
------------------
----- July ------
No purchases...
Monthly points: 0
------------------
------------- August -------------
Purchase: $301, points: 452
Purchase: $149, points: 148
Purchase: $135, points: 120
Purchase: $263, points: 376
Purchase: $264, points: 378
Purchase: $95, points: 45
Purchase: $383, points: 616
Purchase: $292, points: 434
Purchase: $56, points: 6
Purchase: $164, points: 178
Purchase: $17, points: 0
Purchase: $325, points: 500
Monthly points: 3253
------------------------------------
------------- September -------------
Purchase: $220, points: 290
Purchase: $279, points: 408
Purchase: $308, points: 466
Monthly points: 1164
------------------------------------
TOTAL POINTS: 2010 (March) + 0 (April) + 0 (May) + 0 (June) + 0 (July) + 3253 (August) + 1164 (September) = 6427
------------------------------------
While the bulk of what I would like the program to do is done, there are numerous limitations on what this program can do given different parameters.
- There is no option for storing more than a year's worth of purchases. Every customer can only have a maximum of 12 months of purchases history (will be added in the future most likely)
- There are also no day or time identifiers for any purchase added to a month. This was also something I wanted to add, but just didnt get to becuase of time.
monthFromandmonthTomust be months that were listed in the cases. To create a month with o purchase history you must specify it by typing0 monthmonthFromandmonthTorange selectors cannot be used to wrap around a year (haven't figured how to implement this yet). For instance, in the example aboveNovember Marchis invalid.- There are probably more, but I can't think of the rest right now (will updated as needed)