Object-Oriented Programming with Web Apps Problem Set 1

CMPSC 221.1 – Object-Oriented Programming with Web Apps

Problem Set 1
The following problem set will be worth 100 points. The code will be submitted electronically via
Canvas using the “Problem Set 1” dropbox. The assignment is due at the start of the class two weeks
from the date it was assigned.
Your code will be graded on both elegance and user-friendliness.
Exercise #1 – Fraction Problem (10pts)
Define a class called Fraction. This class is used to represent a ratio of two integers. Include mutator
methods which allow users to set values for the numerator and the denominator. Also include a method
that returns the value of the numerator divided by the value of the denominator as a double. Include an
additional method that outputs the value of the fraction reduced to lowest terms (e.g. instead of
outputting 20/60, output 1/3.) This will require finding the greatest common divisor for both the
numerator and denominator, and then dividing both by that number. Include testing examples in the
main method of your class.
Save your solution in the file named Fraction.java.
Exercise #2 – Driving Problem (10pts)
Create a Java class named Odometer which can be used to calculate fuel and mileage for an
automobile. The class should have instance data which tracks the miles driven and the fuel efficiency
in miles per gallon. Include a mutator method to reset the odometer to zero miles, a mutator method to
set the fuel efficiency, a mutator method which accepts the miles driven for a trip and adds it to the
odometer’s total, and an accessor method that returns the number of gallons of gasoline that the vehicle
has consumed since the last reset. Include a main method that creates an instance of the class and
invokes the methods for testing.
Save your solution in a file named Odometer.java.
Exercise #3 – Seating Problem (20pts)
Assume an airplane seats passengers with seat numberings as follows:
1 A B C D
2 A B C D
3 A B C D
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4 A B C D
5 A B C D
6 A B C D
7 A B C D
Write a class named Airplane which holds this seating arrangement in some sort of data structure (two
dimensional array or Java collection class or similar.) Write a main method in this class which will
loop, allowing the user to enter a row number and column letter for each seat occupied until no more
seats need to be added. Print out the grid after each pass of the loop, marking each assigned seat with
an X. Show the user an error message if the user attempts to set an already assigned seat.
Save your solution in a file named Airplane.java.
Exercise #4 – Queueing Problem (20pts)
In data structures, a queue is a data structure that is “first in, first out”. It contains two methods:
• enqueue – adds an item to the queue
• dequeue – removes an item from the queue
For this assignment you are going to implement a variation on this called a priority queue, where an
integer corresponding to the priority is passed into the enqueue method upon invocation. As an
example, we can have three successive calls to add items to the queue:
• q.enqueue(“X”, 10)
• q.enqueue(“Y”, 1)
• q.enqueue(“Z”, 3)
Invoking dequeue on the object will then remove the item “X” from the queue, since it has the highest
priority. A second invocation of the method returns “Z” while the third invocation returns “Y”. Use an
ArrayList as a representation of the queue. Include a main method which demonstrates successive
adds and removals from your queue.
Save your solution in a file named PriorityQueue.java.
Exercise #5 – Pizza Problem (15pts)
Create a class named Pizza that stores information about a single pizza. It should contain the
following:
• private instance variables to store the size of the pizza (small, medium, large), number of cheese
toppings, number of pepperoni toppings and the number of ham toppings
• Constructor(s) that set all instance variables
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• Public methods to get/set the instance variables
• A public method named calcCost() that returns a double that is the cost of the pizza. Pizza cost
is determined by:
o Small: $10 + $2 per topping
o Medium: $12 + $2 per topping
o Large: $14 + $2 per topping
• A public method named getDescription() that returns a string containing the pizza size, quantity
of each topping and the pizza cost as calculated by calcCost().
Write test code to create several pizzas and their descriptions in the main method of the class. For
instance a large pizza with one cheese, one pepperoni and two ham toppings should cost $22. Name
your class Pizza.java.
Exercise #6 – Number List Problem (15pts)
Write a program that reads numbers from the keyboard into an array of type int[]. You can assume that
there won’t be more than 50 elements added to the list. Your output should be a two column list. The
first is the set of distinct array elements, the second column is the number of occurrences of each
element. The list should be sorted on entries in the first column, largest to smallest. As an example for
the array itself:
{-12, 3, -12, 4, 1, 1, -12, 1, -1, 1, 2, 3, 4, 2, 3, -12}
Your output should look like the following:
N Count
4 2
3 3
2 2
1 4
-1 1
-12 4
Save your solution in a file named IntList.java.
Exercise #7 – Doctor Problem (10pts)
Give the definition of a class named Doctor whose objects are records for a clinic’s doctors. This class
will be a derived class of the class SalariedEmployee. A salaried employee consists of:
• First Name (String)
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• Last Name (String)
• Hire Date (String)
• Salary (double)
A Doctor record has the doctor’s specialty (such as “Pediatrician”, “Obstetrician”, “General
Practitioner”, and so forth; so use the type String) and office visit fee (use type double.) Be sure your
class has a resolvable complement of constructors, accessor and mutator methods, and suitably defined
equals and toString methods. Write a program to test all of your methods.
Submission Requirements: Submit the aforementioned files in a zip file with the naming strategy:
First initial + last name + PS + problem set number.zip
As an example, I would submit the code in a zip file named mmeluskyPS1.zip. Submit your zip file
via the “Problem Set 1” Canvas dropbox before the date of the close of the assignment.