# Assignment 3 – Inheritance, Abstract Classes, Interfaces, and Polymorphism
## Due: 02-19-2020
## Author
## Description
The Jawas on Tatooine have recently opened a droid factory and they want to hire you to write a program to hold a list of the available droids, and the price of each droid. The price is based on the type: (protocol, utility, janitor, or astromech), the material used and the options selected by the Jawa creating the list.
The program will keep a list of Droids that are created. This list MUST be an Array. The array should be of a type that is high enough on the inheritance chain that all droids no matter what type they are can be stored in it (Think Polymorphism). Don’t make it of type ‘object’. That is too high on the inheritance chain. Also, just make the size of the array large enough that it can accommodate some droids. 100 is a good number that comes to mind. I’m not concerned with it being auto-resizing, or anything fancy.
A Jawa will be presented with a user interface to add a new Droid, or print the current Droid list. Adding a new Droid will require input from the Jawa to create the new droid. Once all of the needed information is added for the droid, the new droid will be added to the droid collection.
If a Jawa decides to print the collection of droids in inventory, the program should loop through all of the droids in the collection and print out the information from ToString, and the TotalCost for each droid. This should be accomplished using Polymorphism to reduce the amount of code needed.
All of the prices for the various aspects of a droid are left up to you to determine. If I was doing it though, I would probably have a small set price for each of the following general options, and not get too specific to save time. ie:
1. A price for model(protocol, utility, etc.)
2. A few different materials (Something Made up), each with a different price
3. A price for each additional option (One of the various option bools listed below. One price for all will work)
4. A price per quantity option such as: numberOfLanguages, and numberOfShips
The program comes with an Interface IDroid that must be implemented by subclasses. It contains a public method called CalculateTotalCost, and a public Property called TotalCost. CalculateTotalCost returns a void, so it’s job is to access the properties of the droid and literally calculate the total cost. It does not return the Total Cost. It only Calculates it.
TotalCost is how you will get access to the total cost of the droid. This will be zero until CalculateTotalCost is called. Then it will have a value.
I didn’t make CalculateTotalCost return the calculated value because I wanted you to have to implement both a method and a property in subclasses. This should also demonstrate how an Interface acts as a contract and requires you to write things a certain way. Even if you don’t agree with it.
You should put all of your UI into a UI class that will handle getting all of the necessary information from the Jawa, and display the feedback to the Jawa.
You should create a class for the collection of the Droids. The DroidCollection class should contain the array that holds the droids, and maintain any internal information needed to manage that array. It should have an add method that will do the work of determining which instance of a droid needs to be created and added to the array. The UI class will prompt for the needed information to add a droid, and then when it has all of the info, it will send it to the add method, which will then determine which type to add based on the ‘model’ that was entered. The add method might be a good place to do method overloading, though not required.
You should follow the concepts about inheritance talked about in class, and work hard at DRY (Don’t Repeat Yourself) Principles.
## Classes
The program should have a base abstract class called Droid with the following variables, properties, constructors, methods, etc that implements the IDroid interface.
Droid:
* Variables: material (string), color (string), baseCost (decimal), totalCost (decimal)
* Constructors: 2 parameter constructor (string, string)
* Property: TotalCost to return the cost of the droid (Required by the interface)
* Public Methods:
* ToString: return a formatted string containing the variables
* CalculateTotalCost: Required by the interface
* Protected Methods:
* CalculateBaseCost: Determines the baseCost based on material and color.
There should be two derived classes from the abstract class Droid with appropriate variables, methods and properties.
Protocol:
* Variables: numberLanguages (int)
* Constant: costPerLanguage
* Constructors: 3 parameter constructor (string, string, int)
* Uses the base class (Droid) constructor
* Public Methods:
* ToString: return a formatted string containing the variables
* CalculateTotalCost: Calculate the totalCost based on the number of languages and type, and then adds it to the base totalCost
Utility:
* Variables: toolbox (bool), computerConnection (bool), arm (bool)
* Constructors: 5 parameter constructor (string, string, bool, bool, bool)
* Uses the base class (Droid) constructor
* Public Methods:
* ToString: return a formatted string containing the variables
* CalculateTotalCost: Calculates totalCost by calculating the cost of each selected option and type, and then add it to the base totalCost.
There should be two more derived classes from the class Utility with appropriate variables, methods and properties.
Janitor:
* Variables: trashCompactor (bool), vacuum (bool)
* Constructors: 7 parameter constructor (string, string, bool, bool, bool, bool, bool)
* Uses the base class (Utility) constructor
* Public Methods:
* ToString: return a formatted string containing the variables
* CalculateTotalCost: Calculate totalCost by calculating the cost of each selected option and type, and then adds it to the base CalculateTotalCost
Astromech:
* Variables: fireExtinquisher (bool), numberShips (int)
* Constant: costPerShip
* Constructors: 7 parameter constructor (string, string, bool, bool, bool, bool, int)
* Uses the base class (Utility) constructor
* Public Methods:
* ToString: return a formatted string containing the variables
* CalculateTotalCost: Calculate totalCost by calculating the cost of each selected option, the cost based on the number of ships, and the type. Then add all of that to the base CalculateTotalCost
## Solution Requirements
Solution Must:
* Allow Jawa to add a new droid of either (Protocol, Utility, Janitor, or Astromech) to the list
* Allow Jawa to print the list of droids out.
* Create abstract class Droid that implements IDroid
* Derive two classes (Protocol and Utility) from the class Droid
* Derive two classes (Janitorial and Astromech) from the class Utility
* Each derived class (Protocol, Utility, Janitor, and Astromnech) must either implement or override the ToString and CalculateTotalCost methods
* Create a UI class
* Create a DroidCollection class
* Use private, public and protected appropriately.
* Use abstract, virtual, and override appropriately.
* Have sufficient comments about what you are doing in the code.
### Notes
If you did not do well on Assignment 1, you may want to look at the Assignment 1 Key that I did for some help related to UI classes, Collection classes, arrays, and structure.
It may be beneficial for you to create extra methods within the droid sub classes. You are not limited to the ones mentioned. You may even find it useful to make some additional ones that are protected and virtual.
## Grading
| Feature | Points |
| ————————– | —— |
| Droid Class | 10 |
| Protocol / Utility | 15 |
| Janitor / Astromech | 15 |
| ToString / Total Cost | 10 |
| UI Class | 10 |
| Droid Collection | 10 |
| Add Droid / Print List | 10 |
| Access Modifiers Correct | 5 |
| Abstract / Virtual Correct | 5 |
| Documentation | 5 |
| README | 5 |
| **Total** | **100**|
## Outside Resources Used
StackOverFlow.com
prior assingments or inclass work
## Known Problems, Issues, And/Or Errors in the Program
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