Spring 2018 CS230

This is a course about data structures and we happen to use java,
an "Object-Oriented" programming language.

About CS230

big ideas in this course

  • Data Abstraction - Separate a program's behavior from its implementation
  • Modularity - Reusable components with standard interfaces
  • Performance Analysis - How efficient is your code with respect to space and time?
  • Standard Abstract Data Types - We'll cover the classical data structures including lists, stacks, queues, trees, tables and graphs.

Meet your instructors & tutors

Click here for CS230 drop-in calendar

CS230 Spring 2018 schedule

It is REQUIRED that you do the reading before the class and submit a reading response by 7AM on class days.
Please check this page frequently, as it is subject to change.







Lecture 1: Intro to CS230
Reading: LDC Ch 1 & 2

Entry questionnaire

(slides / code)


Lecture 2: Java constructs, conditionals, iteration
Reading: LDC Ch 3 & 4. (Optional: 3.6 Formatting Output; 3.7 Enumerated Types.)

(slides / code)



Lecture 3: User-defined java classes
Reading: LDC Ch 5

(slides / code)


Lecture 4: Arrays
Reading: LDC Ch 7

(slides / code)



Lecture 5: Arrays of Objects and Inheritance!
Reading: LDC Ch 7 & 8

(slides / slides / code)


Lecture 6: Polymorphism via inheritance
Reading: LDC Ch Ch 9.1 - 9.2
(slides / code)



Presidents' Day - No Classes


MONDAY Schedule

Lecture 7: Interfaces and Exceptions
Reading: LDC Ch 9.3 - 9.4 & Ch 10 (except 10.4)
(slides / code)


In-class Midterm Exam 1


Deadline to DROP a spring course at 11 PM


Lecture 7: Interfaces and Exceptions
Reading: LDC Ch 9.3 - 9.4 & Ch 10 (except 10.4)
(slides / code)



Lab5: Repeat of Lab4

Reading: Tutorial on Vectors


Lab5: Repeat of Lab4

Reading: Tutorial on Vectors


Lecture 8: Collections and Stacks
Reading: LDC Ch 14.1 - 14.9
(slides / code)



Lecture 9: Linked Lists
Reading: LDC Ch 14.10 - 14.14
(slides / code)

Assign4 due on Mar 4 at 11:59 PM


Lecture 11: Queues
Reading: LDC Ch 15.1 - 15.5
(slides / code)



Lecture 10: Analysis of Algorithms
Reading: LDC Ch 12



Take-home Exam 2 out

Lecture 13: Hash tables
Reading: LDC Ch 20
(slides / code)



Lecture 12: Searching and Sorting
Reading: LDC Ch 13
(slides / code)


Pre-lab 8

Lab 8: Hash Tables

Take-home Exam 2 due at 11:59PM


Spring Break


Spring Break


Spring Break


Spring Break


Spring Break


Spring Break


Spring Break


Lecture 16: Graphical User Interfaces
Reading: LDC Ch 6.1, 6.2
(slides / code)


Lecture 17: GUIs (cont.)
Reading: LDC Ch 6
(slides / code)

Preparation for Project



Lecture 14: Introduction to Graphs, DFS
Reading: LDC Ch 19.1 - 19.5


Pre-lab 10

Lab 10: Graphs

Assign6 due at 11:59 PM


Lecture 15: Graph traversals, Topological sort
Reading: LDC Ch 19.5

Project Description email (Phase 0)



Patriots' Day No Classes


Reading: LDC Ch 16.1, 16.2, 16.3

Lab 11: Graphs continued


Reading: LDC Ch 16.1, 16.2, 16.3

Lab 11: Graphs continued


Lecture 18: Trees

(slides / code)




In class Review

Project Specification (Phase 1)


Pre-lab 11

Lab 11: Trees


Pre-lab 11

Lab 11: Trees

Assign7 due at 11:59 PM

Assign7 due at 11:59 PM



Lecture 19: Link-based Tree implementation
Reading: LDC Ch 16.4




Lecture 20: Decision Trees
Reading: LDC Ch 16.5

Take-home Exam 3 out




Ruhlman Conference No Classes


Lecture 21: Priority Queues and Heaps
Reading: LDC Ch 18


In-class presentations

anonymous feedback form


Take-home Exam 3 due at 11:59PM


Lecture 22: Binary Search Trees
Reading: LDC Ch 17.1, 17.2, 17.3
(slides )


Lab 13

In-class Presentations (Phase 2)


Lab 13

In-class Presentations (Phase 2)


Lecture 26

In-class Presentations (Phase 2)


Last day of classes


Reading period


Reading period


Reading period


Reading period

Administrative details of CS230

Course Overview

Prerequisites The prerequisite for CS230 is CS111, Computer Programming and Problem Solving. Students with significant programming experience (including knowledge of Java), or those who have received less than a B- in CS111 need the permission of the instructor.

Computers All programming in CS230 will be done using the BlueJ Java Development Environment. If you want, you can use your own computer but you will have to maintain the software, and be prepared to use the department's machines if yours has problems. Sorry, we will not be able to help you trouble-shoot your own computer.

Course Directory The CS230 course directory is located at /home/cs230 on tempest. This directory contains material relevant to the class, including course software, and online versions of assignments and programs. Any required material of the course Java software will be placed in the download folder inside the /home/cs230 directory and you can access it using an ftp program (like Fetch on a Mac).

Course Group Please add yourself to the CS230-S18 google group. This group has several purposes. We will use it to make class announcements, such as corrections to assignments and clarifications of material discussed in class. We encourage you to post questions or comments that are of interest to students in the course. Please do not post significant amounts of Java code (i.e. more than one or two lines of code) in your messages on the group! The instructors and TAs will read messages posted in the group on a regular basis and post answers to questions found there. If you know the answer to a classmate's question, feel free to post a reply yourself. The course group is also a good place to find people to join a study group. You should plan on reading group messages on a regular basis.

Textbook Regular readings will be assigned from the required text, Java Foundations, by Lewis, DePasquale and Chase, 2nd edition. We will be using the 2nd edition (not the newer, 3rd edition). It is on reserve in the Science Library. It is required that you read the relevant sections prior to class and submit a reading response.

Java Documentation Being able to understand and use the official Java Documentation is a characteristic of every successful programmer. Become familiar with it!

SI Materials The SIs have shared this Google Drive folder of materials with you, so here's a helpful link to make it easier for you to in find it. This folder will include all the handouts they have shared with you in SI.

How to succeed in CS230

Your instructors want you to succeed, and we will do all we can to help you learn the material and become a strong programmer. From your side, here are a few things you can do to succeed in this course.
  • Plan on spending about 11 hours per week (outside of lecture and lab). If you consistently spend more than that time, please see your professor.
  • Early in the semester drop by your instructors' office hours and introduce yourself. If you can't make it to regular office hours email your instructors to make an appointment.
  • When working on course materials, turn off your social media.
  • Attend all lectures, quit all social media while in class.
  • Attend all labs, quit all social media while in class.
  • Read the book and slides BEFORE attempting to do the homework, and submit your reading responses on time.
  • Read homework description immediately, start thinking about it ASAP, not 1-2 days before it is due!
  • Start homework early, be prepared to make mistakes.
  • Do not expect to finish your homework in one day. Plan ahead so that you can divide the work across different days.
  • Programming is a skill: The best programmer has made every mistake in the books!
  • Programming is hard: Do not blame yourself for your mistakes; just give yourself more time!
  • Remember: "Help will always be given at Hogwarts to those who ask for it.” ― J.K. Rowling, Harry Potter and the Deathly Hallows. Your instructors, SI, and TAs are here to help.

Course Requirements

Lectures and Labs There are two 70-minute lectures each week that will introduce the main content of the course. Every student is also required to attend one 110-minute lab each week. Lab work will include exercises to review and reinforce the lecture material and to develop general programming, testing and debugging skills. The labs will also provide further opportunity to ask questions about course material. Lectures are held on Mondays and Thursdays at 9:50-11:00 AM (section 01 in SCI E111), at 11:10AM-12:20PM (section 02 in SCI 270). In labs you will be working either with a partner, or individually. In general, be aware that labs contain more tasks than can reasonably be done in the available class time. Solutions to lab exercises will be provided at the end of the day; you are encouraged to study these solutions. At the end of the day of your lab, each student is required to submit whatever lab work they have worked on until then. These submissions will be part of the student's participation grade (see "Grading Policy").

Supplemental Instruction (SI) Supplemental Instruction (SI) is an academic support program offered for selected Wellesley courses. Our academic SI leader, Priscilla Lee, is trained and highly experienced in tutoring CS230. She will offer two study sessions each week throughout the semester. During SI sessions she will cover problem set solutions and review important concepts. SI sessions are open to all students enrolled in the course. We highly recommend attending one of the SI sessions every week, as well as reviewing the handouts used in SI sessions.

Final Project: During the last few weeks of the semester, project teams of 3 students work on an extended programming project from scratch. After choosing an interesting application or problem, you will first build a skeleton of the object classes, methods, abstract data types and user interface needed for your application, and then fill in the details to create a fully working implementation. Each team will give a short presentation of their final project during the last week of the semester, and will prepare a document with specifications, user's manual, code and documentation on their final project. Guidelines will be posted mid-semester. See our CS230 project gallery for information on student projects from recent semesters.

Exams: There will be three in-term, non-collaborative exams. The first is in-class and the other two are take-home. There will be no final exam. For the in-class exam you can use the course handouts and your personal notes only. The take-home exams will require the use of a computer. You are not allowed to collaborate with anyone else on any of the exams, including the take-home exams. The dates of the exams are listed on the schedule. Please mark the exam dates in your calendars.

Grading Policy

Assignments For assignments, normally a subset of assigned problems will be graded. The full credit of the assignment will be based on the graded subset. After assignments are submitted, sample solutions will be provided for all assigned problems.

Participation Lecture and lab participation has a weight of 10% of the total course grade. Participation includes attendance, submitting reading responses, active articipation in class discussions, and completing lab tasks and questionnaires.

Final Grades Your final grade for the course will be computed as a weighted average of several components. The relative weight of each component is shown below:

  • Assignments: 25%
  • Final Project: 10%
  • Exam 1 (in-class): 15%
  • Exam 2 (take-home): 20%
  • Exam 3 (take-home): 20%
  • Class Participation: 10%
  • Total: 100%
Note that each assignment corresponds to about 3% of your final grade, and each lab to about 1% of your final grade. This course complies with the Wellesley College grading policy. While that policy asks faculty to hold each 100- and 200-level course with 10 or more students to an average of no higher than 3.33, it does not require faculty to grade on a "curve." There is no arbitrary limit on the number of A's, B's, C's etc., and every student will be assigned the grade they earn and deserve according to the grading standards of the college.

Assignments in CS230

There will be weekly assignments in which you will write Java programs that emphasize concepts discussed in class. Many of the assignments will be challenging. You are required to work with a partner on the marked task(s) on each of the assignments. Keep in mind that programming often consumes more time than you expect. Start your assignments early! This will give you time to think about the problems and ask questions if you hit an impasse. Assignments are due as indicated on the class schedule. You should also submit a hard copy at the beginning of your next class.

A running program is just the beginning. A program submitted that runs correctly on a particular input earns only 60% of the total grade. Careful testing that covers both the basic functionality and border cases will earn another 20% of the grade, if the testing is demonstrated. The remaining 20% of the grade is earned for good design that implements OOP, documentation that includes top-of-the-file description, method explanation, and in-line explanation as needed. Good programming style is also expected.

Late Assignment Policy. If you are unable to complete any assignment by the extended due date, you are required to contact your instructor prior to the due data in order to discuss the assignment and ensure that you have a plan and a schedule for completing the assignment. You must contact them to set up a time to talk, or find them at office hours.
If the formal solutions to an assignment are distributed before you turn in a late assignment, you are bound by the Honor Code not to examine these solutions.

Collaboration Policy

Here is overview on our collaboration policy, and it is followed by a more detailed explanation below:
  • Assignments: Pairs of students.
  • Project: Teams of 3 students
  • Exams: Absolutely no collaboration

We believe that collaboration fosters a healthy and enjoyable educational environment. For this reason, we encourage you to talk with other students about the course material and to form study groups.

Programming assignments in this course can be challenging. Also teamwork is the norm in the CS industry. Given the above, some of the assignment work is required to be done with a partner, while some is required to be done individually. In each assignment tasks will be clearly marked as either "individual" or "pair-programming". The two team members must work closely together on the pair-programming tasks, and turn in a single hard copy of work they did together.

Pair-programming tasks are subject to the following ground rules:

  • Each team member has to read the assignment problems, think of how to go on solving it, and sketch some solutions, before meeting with their partner.
  • While working together, the work must be a true collaboration in which each member of the team will carry her own weight. It is not acceptable for two team members to split the work between them and work independently.
  • The fact that team members have to program together means that you need to carefully consider a potential partner's schedule before forming a team. You cannot be an effective team if you cannot find large chunks of time to spend at a computer together!
  • Except for the first assignment, when submitting an assignment, you have to decide on your partner for the next assignment.
  • Working with different partners is a good way to build community in the class. We strongly recommend that you pair up with several other students during the semester.

In general, teams are allowed to discuss assignment tasks with other teams and exchange ideas about how to solve them. However, the work you turn in should be that of your partnership only. Do not copy or plagiarize the work of others.

Each team or individual student must compose their own solution to each task. Discussing strategies and approaches with classmates and receiving general debugging advice from them is acceptable and encouraged. However you (and your partner) are required to write and debug all of your code. Furthermore, you should never look at another student's code. For example, it is OK to borrow code from the textbook, from materials discussed in class, and from other sources as long as you give proper credit. However, it is unacceptable and constitutes a violation of the Honor Code (1) to write a program together with someone not part of your team and turn in two copies of the same program, (2) to copy code written by your classmates, (3) to read another student's or team's code (4) to view assignments, exams and solutions from previous terms of CS230 or (5) to make any of the assignments, exams and solutions available to others online or off-line. In keeping with the standards of the scientific community, you must give credit where credit is due. If you make use of an idea that was developed by (or jointly with) others, please reference them appropriately in your work. It is unacceptable for students to work together but not to acknowledge each other in their write-ups.

Anonymous Feedback Form

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To give anonymous feedback to the CS230 instructors about the course,
please use the Anonymous Feedback Form