Object-Oriented Programming II Assignment # 1 


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COMP249 – Assignment 1
Comp 249 –
Object-Oriented Programming II
Assignment # 1
Purpose: Practically, this assignment should be considered as Assignment # 0! The purpose of this
assignment is to help you review some of the main topics covered in previous courses, including classes,
loops, arrays, arrays of objects, static attributes and static methods.
General Guidelines When Writing Programs:
– Include the following comments at the top of your source codes
// —————————————————–
// Assignment (include number)
// Question: (include question/part number, if applicable)
// Written by: (include your name and student id)
// —————————————————–
– In a comment, give a general explanation of what your program does. As the programming
questions get more complex, the explanations will get lengthier.
– Include comments in your program describing the main steps in your program.
– Display a welcome message which includes your name(s).
– Display clear prompts for users when you are expecting the user to enter data from the keyboard.
– All output should be displayed with clear messages and in an easy to read format.
– End your program with a closing message so that the user knows that the program has terminated.
JavaDoc Documentation:
Documentation for your program must be written in JavaDoc. In addition, the following information must appear at the top of each file:
Name(s) and ID(s) (include full names and IDs)
Assignment # (include the assignment number)
Due Date (include the due date for this assignment)
Part I)
An appliance object has four attributes, a type (String), a brand (String), a serial number (long),
and a price (double). The type of an appliance can be any of the following: Fridge, Air
Conditioner, Washer, Dryer, Freezer, Stove, Dishwasher, Water Heaters, and Microwave. The
brand indicates the vendor/manufacturer of the appliance (such as LG, Samsung, Bosch, etc.),
and can be any string. The serial number represents the serial number of the appliance, and must
be unique. For simplicity, we assume that the serial numbers start at 1000000 and it is
common/shared among all different brands and types (for example, if the creation of objects
starts by a Washer created by Maytag, then it will be assigned serial number 1000000. If a
Microwave by Breville is created next, then it will be assigned serial number 1000001, and so on
afterwards). The price of an appliance cannot be less than 1$. (Hint: Static – You are allowed to
add other attributes to the class.)
For this part, you are required to design and implement the Appliance class according to the
following specifications:
COMP249/Fall 2019 – Assignment 1 Page 2 of 5
What do you want to do?
1. Enter new appliances (password required)
2. Change information of an appliance (password required)
3. Display all appliances by a specific brand
4. Display all appliances under a certain a price.
5. Quit
Please enter your choice >
– Upon the creation of an appliance object, the object must immediately be initialized with
valid values; that is type, brand, serial number and price. (Hint: Constructors.)
– The design should allow enough flexibility so that the value of any of these attributes can
be modified later on (with the exception of the serial number, which can never be
changed once assigned). For example, it should be possible to create an appliance object
with a given price then change its price later on. Notice that changes to brand or type is
allowed (although this is unusual in reality!). The design should also allow the user to
obtain the value of any of the attributes. (Hint: Accessors & Mutators.)
– The design should allow all information of an object to be displayed at once through the
utilization of System.out.print() method. (Hint: toString() method)
– It is required to know how many appliance objects have been created. For that, you need
to add a method, called findNumberOfCreatedAppliances(), to the class. This method
must return the number of created appliance objects prior to the time this method is
called. The method would simply return 0 if no appliances have been created by the time
the method is called.
– It is required to compare two Appliance objects for equality. Two appliances are
considered equal if they have the same brand, type and price. (Hint: equals() method)
– It is required to display any Appliance object (all info of that object) using
System.out.println() method. (Hint: toSting() method)
Part II)
You are hired by a major appliance dealer to write a software that helps the store owner in acquiring and
keeping track of appliances at the store. Write a driver program that will contain, at least, the following
methods. Note: You can have the main function in a separate driver file, or in the same file if you prefer.
1. a main() method, that will:
a. Display a welcome message;
b. Prompt the store owner for the maximum number of appliances (maxAppliances) his/her
store can contain (or wish to aquire; this is not a focus here). Create an empty array, called
inventory, that will have the potential of keeping track of the created Appliance objects.
c. Display a main menu (Figure 1) with the following choices and keep prompting the user
until they enter a number between 1 and 5 inclusive (i.e invalid number will result in
repeating the display of the main menu):
Figure 1. Main
COMP249/Fall 2019 – Assignment 1 Page 3 of 5
d. When option 1 is entered:
i. Prompt the store owner for his/her password. (Make sure you have a constant variable
containing the password “c249” – do not use any other password as it will be easier for
the marker to check your assignments). The store owner has a maximum of 3 attempts to
enter the correct password. After the 3rd illegal entry, the main menu in Figure 1 is redisplayed again. Additionally after this process is repeated 4 consecutive times (i.e. total
failed attempts is 12 consecutive attempts by now), the program must display the
following messages: “Program detected suspicious activities and will terminate
immediately!”, then the program must exits.
ii. If the correct password is entered (which will reset the counter of failed attempts), ask the
owner how many appliances he/she wants to enter. Check that there is enough space in
the store (inventory array) to add these many appliances. If so, add them; otherwise
inform the owner of the maximum remaining places in the array. (How the appliance
information is input/entered by the user is up to you).
e. When option 2 is entered:
i. Prompt the store owner for his/her password. (Still, you should make sure the
password is “c249” – do not use another password). Again the store owner has 3
attempts to enter the correct password. However, after the 3rd illegal entry, the main
menu in Figure 1 is simply re-displayed again (notice the different behaviour in that
case from the previous one above).
ii. Ask the user of the serial number of the appliance he/she wishes to update. If there
is no object with that serial number in the array inventory, display a message
indicating that and ask the user if he/she wishes to re-enter another serial number,
or quit this operation and go back to the main menu. If the entered serial number
exists, display the current information of that appliance in the following format:
Appliance Serial # xxxxxxx (where xxxxxxx is the serial number)
Brand: brand of the appliance
Type: type of the appliance
Price: price
Then ask the user which attribute he/she wishes to change by displaying the
following menu.
Once the user has entered a correct choice, ask the user for the new information and make
the changes to the object attribute then display again all of the attributes on the screen to
show that the change has taken place. Keep prompting the user for additional changes until
the user enters 4 (indicating that he/she wishs to stop the update process). Each time the
user is prompted for a choice, make sure that a number from 1 to 4 is entered, otherwise
keep prompting until a valid number is entered. You should pay a special attention to the
What information would you like to
1. brand
2. type
3. price
4. Quit
Enter your choice >
Figure 2. Update
COMP249/Fall 2019 – Assignment 1 Page 4 of 5
change when it comes to type, as the different types are specific and limited (cannot be
different than the types indicated in the initial description in Part I above).
f. When option 3 (in the main menu shown in Fig. 1) is entered, prompt the user to enter a
brand name. You then need to display the information of all appliances in the inventory
with that brand. (Hint: You may use a static method, for instance called findAppliancesBy,
which accepts a string for an brand name then performs the needed search).
g. When option 4 (in the main menu shown in Figure 1) is entered, prompt the user to enter a
value (representing a price). You then need to display all appliances in the store that have a
price smaller than that entered value. (Hint: You may use a static method, for instance
called findCheaperThan, which accepts a double value, for a price, then performs the
needed search).
h. When option 5 (in the main menu shown in Fig. 1) is entered, display a closing message
and end the program.
Submitting Assignment 1
– For this assignment, you are allowed to work individually, or in a group of a maximum of 2
students (i.e. you and one other student). You and your teammate must however be in the same
section of the course. Groups of more than 2 students = zero mark for all members!
– Only electronic submissions will be accepted. Zip together the source codes. (Please use
– Students will have to submit their assignments (one copy per group) using the Moodle/EAS
system (please check for your section submission). Assignments must be submitted in the right
DropBox/folder of the assignments. Assignments uploaded to an incorrect DropBox/folder
will not be marked and result in a zero mark. No resubmissions will be allowed. Your
instructor will indicate whether you should upload your assignment to EAS
( or to Moodle.
– Naming convention for zip file: Create one zip file, containing all source files and produced
documentations for your assignment using the following naming convention:
The zip file should be called a#_StudentName_StudentID, where # is the number of the
assignment and StudentName/StudentID is your name and ID number respectively. Use
your “official” name only – no abbreviations or nick names; capitalize the usual “last”
name. Inappropriate submissions will be heavily penalized. For example, for the first
assignment, student 12345678 would submit a zip file named like: if working in a group, the name should look like:
– Submit only ONE version of an assignment. If more than one version is submitted the first one
will be graded and all others will be disregarded.
– If working in a team, only one of the members can upload the assignment. Do NOT upload the
file for each of the members!
 Important: Following your submission, a demo is required (please refer to the courser
outline for full details). The marker will inform you about the demo times. Please notice
that failing to demo your assignment will result in zero mark regardless of your
COMP249/Fall 2019 – Assignment 1 Page 5 of 5
Evaluation Criteria for Assignment 1 (10 points)
Documentations 1 pts
JavaDoc documentations 1 pt
Part I (Class Appliance) 3 pts
Default & copy constructors 1 pt
Accessor/mutator method for static attribute 1 pt
equals, toString and static attributes/methods 1 pt
Part II (Driver & other static methods) 6 pts
Handling of password 1 pt
Handling of option 1 1 pt
Handling of options 2 & 3 1 pt
Handling of options 4 & 5 1 pt
General quality and correctness of code & functionality 2 pts

Object-Oriented Programming II Assignment # 1 
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