Class Info

Section 1: MWF 9:30–10:20, Sci Cntr 240
Professor: Tia Newhall
email:
Office hours: 1-2pm Mondays, and by appointment

Welcome to CS21. This course will introduce fundamental ideas in computer science while also teaching you how to write computer programs. We will study algorithms for solving problems and implement solutions in the Python programming language. Python is an interpreted language that is known for its ease of use. We also introduce object-oriented programming and data structures. A deeper coverage of these topics will be presented in CS 35.

This course is appropriate for all students who want to learn how to write computer programs and think like computer scientists. It is the usual first course for computer science majors and minors. Students with advanced placement credit or extensive programming experience should place out of this course and instead begin with CS 33 or CS 35.

Required Textbook:

• Python Programming: an Introduction to Computer Science by John Zelle
  ISBN: 978-1-887902-99-1
  (a copy is on reserve at Cornell Library)

Goals for the course:

By the end of the course, we hope that you will have developed the following skills:

• Given a program, be able to simulate on paper how a computer would execute the program, and show the results that would be produced.
• Given a problem, be able to design a clear, concise, and correct pseudocode algorithm to solve it.
• Given a pseudocode algorithm, be able to successfully implement it in Python.
• Be able to use top-down design to sub-divide a large problem into reasonably-sized modular sub-problems.
• Given several algorithms for solving the same problem, be able to analyze which algorithm would be more efficient in terms of running time.
• Develop debugging and unit testing skills. Consistently use these skills while implementing programs.
• Learn to work as part of a team to solve problems starting from design and continuing through to implementation.

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Student Support

CS21 Ninjas are student mentors who will assist me in class and run evening study sessions in the main CS lab.
The CS21 Ninjas (student mentors) are: Sarah Chasins, Stella Cho, Steven Hwang, Joan 0'Bryan, Mark Serrano and Brandon Snuggs

Study sessions

You are invited -- and encouraged -- to participate in Ninja evening study sessions to prepare for quizzes, to discuss programming concepts, and to get friendly assistance in working on lab assignments. Our CS mentoring team is dedicated to helping students, who have no prior knowledge of computer science, learn to program in Python while keeping their senses of humor intact. As an added bonus, free food will be provided at the sessions. The sessions are held:

Weekly Evening Ninja Sessions
Sundays	7-9pm	Sci Center 240
Wednesdays	7-9pm	Sci Center 240

In addition, the Ninjas hold weekly office hours. These are times when you can stop by and get one-on-one or small group help on course topics. These are "paper and pencil" sessions that are exclusively for extra help on course topics and not for help with current lab assignments (the weekly Lab Sessions run by the professors and the Evening Ninja sessions are for lab help).

Weekly Ninja Office Hours
Wednesdays	1:15-4:15	Sci Center 257

Lab Sessions

The CS lab is open 24 hours a day, 7 days a week for you to use for CS21 lab assignments. In addition, the CS21 professors will be in the CS labs at the times listed below to help CS21 students with lab assignments. You are not required to attend any of these sessions, but you should take advantage of them to get assistance with your lab assignments. Any CS21 student is welcome to attend any/all session.

Weekly Lab Sessions
2:30-4:00 Mondays	Newhall	Science Center 240
3:30-5:00 Mondays	Soni	Science Center 240
2:00-3:30 Fridays	Knerr	Science Center 238

Accessing the CS labs after hours

You can use your ID to gain access to the computer labs at nights and on the weekends. Just wave your ID over the microprox reader next to the lab doors. When the green light goes on, just push on the door handle to get in (the door knob will not turn). If the green light doesn't go on, then we need to enter your microprox number into the system. email local-staff@cs.swarthmore.edu if you have problems with this. If the building is locked, you can use your ID to enter the door between Martin and Cornell library. For this class, your ID will give you access to the labs in rooms 238 and 240.

How to Succeed in CS 21

• Attend class.
  The primary introduction to course material is through class lecture. Additionally, we often do lab exercises during class. This is an important part of the learning process, as these exercises give you immediate experience with the material we are covering.
• Read the material before you come to class.
  Don't worry about total comprehension, but at least get a feel for what we will be covering that week. If you have some understanding of the material coming into class, it will be easier for you to ask questions during class, rather than later when help may not be available.
• Ask questions if you don't understand.
  This means both during class and while doing lab assignments . This class continually builds on previous material, so if you don't understand something one week, it will continue to be a problem the next week, and the week after that, and so on. If you need help, ask your classmates (make sure you have read the "Academic Integrity" section below first), attend the lab and study sessions, come talk with me during my office hours, or email me your question.
• Start the lab assignments early.
  I realize this one is not always easy to do, but if you can get in the habit of doing this, you will be much better off. If you get stuck early (i.e., not two hours before it is due), there will be time to look for help. In addition, if you start early enough, you can take a break, go do something else, and come back later. I find I always have at least a few new ideas when I come back to a problem after a break. If you wait until the last minute, you can't do this.
• Practice, practice, practice.
  The only effective way to learn the material and pass the quizes and exams is to consistently do the labs. Finish all of the assigned programs (and do some extras, for fun!). Even if you don't get them done on time, they will still help you learn the material.
• Seek help early and often.
  Because course material builds on previous material, it is essential to your success in this class that you keep up with the course material. If you are having difficulty with a programming assignment, if you didn't follow something covered in lecture, if you feel you need some extra help understanding or practicing some of the course material, or if you just want to discuss something from a lecture, an assignment, or the text, please come to my office hours.
• Attend CS21 Labs and Study Sessions.
  The student Ninjas hold evening study sessions each week. You are encouraged to participate in these sessions. The Ninjas will help you prepare for quizzes, will provide additional instruction in programming concepts, and will provide friendly assistance on your lab assignments. The CS 21 professors hold lab sessions each week. You are encouraged to attend these to get help with lab assignments.
• Take hand written lecture notes.
  In lecture the professor often draws diagrams on the board, some of which you will need to reproduce. Taking notes with paper and pen (vs. on the computer) will allow you to copy these diagrams.

Academic Accommodations

If you believe that you need accommodations for a disability, please contact Leslie Hempling in the Office of Student Disability Services, located in Parrish 130, or e-mail lhempli1 to set up an appointment to discuss your needs and the process for requesting accommodations. Leslie Hempling is responsible for reviewing and approving disability-related accommodation requests and, as appropriate, she will issue students with documented disabilities an Accommodation Authorization Letter. Since accommodations may require early planning and are not retroactive, please contact her as soon as possible. For details about the Student Disabilities Service and the accomodations process, visit the Disability Services webpage.

To receive an accommodation for a course activity, you must have an Accomodation Authorization letter from Leslie Hempling and you need to meet with me to work out the details of your accommodation at least one week prior to the activity.

You are also welcome to contact me privately to discuss your academic needs. However, all disability-related accommodations must be arranged through Leslie Hempling in the Office Of Student Disability Services.

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Grading

Grades will be weighted as follows:

40%	Lab assignments
30%	Quizzes
25%	Final Exam
05%	Class Participation

Quiz policy

Quizzes will be given at the beginning of class on the days posted in the Announcements section of the Schedule. Please look over these dates carefully and contact the professor in advance if you cannot be in class for a quiz.

If you are not present at the start of class on the day of a quiz, but make it to class before the end, then you may take the quiz. Otherwise you will receive a zero for that quiz.

Lab policy

Lab assignments will typically be assigned in class at the beginning of the week and will be due before midnight the following Tuesday night. You are strongly encouraged to start early and to attend the study sessions for extra practice.

You will submit you assignments electronically using the handin21 program. You may submit your assignment multiple times, but each submission overwrites the previous one and only the final submission will be graded.

Late assignments will only be accepted if you contact the professor at least a day before the deadline with a legitimate reason for needing extra time, such as an illness or needing to leave campus.

Even if you do not fully complete an assignment, you should submit what you have done to receive partial credit.

Programming Style

Programming is not a dry mechanical process, but a form of art. Well written code has an aesthetic appeal while poor form can make other programmers and instructors cringe. Programming assignments will be graded based on style and correctness. Good programming practices usually include many of the following principles:

• A comment at the top of the program that includes
  • Program authors
  • Date or Dates
  • A brief description of what the program does
• Concise comments that summarize major sections of your code
• Meaningful variable and function names
• Function comments that include: (1) description of what function does; (2) description of input values (parameter values); (3) description of return value(s)
• Well organized code
• White space or comments to improve legibility
• Avoidance of large blocks of copy-pasted code

Also, look over the Python Code Style Guide for more details and some examples of good code style.

Academic Integrity

Academic honesty is required in all work you submit to be graded. You may not submit work done with (or by) someone else, or examine or use work done by others to complete your own work. Your code should never be shared with anyone; you may not examine or use code belonging to someone else, nor may you let anyone else look at or make a copy of your code. This includes sharing solutions after the due date of the assignment.

All code you submit must be your own with the following permissible exceptions: code distributed in class, code found in the course text book, and code worked on with an assigned partner. In these cases, you should always include detailed comments that indicates on which parts of the assignment you received help, and what your sources were.

Discussing ideas and approaches to problems with others on a general level is fine (in fact, we encourage you to discuss general strategies with each other), but you should never read anyone else's code or let anyone else read your code. You may discuss assignment specifications and requirements with others in the class to be sure you understand the problem. In addition, you are allowed to work with others to help learn the course material. However, with the exception of your lab partner, you may not work with others on your assignments in any capacity.

``It is the opinion of the faculty that for an intentional first offense, failure in the course is normally appropriate. Suspension for a semester or deprivation of the degree in that year may also be appropriate when warranted by the seriousness of the offense.'' - Swarthmore College Bulletin (2008-2009, Section 7.1.2)

Please see me if there are any questions about what is permissible.

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Schedule

This is a tentative schedule; it may change as we go.

WEEK	DAY	ANNOUNCEMENTS	TOPIC & REFERENCES	INCLASS & ASSIGNMENTS
1	Aug 29	Using Unix (240 SciCntr): Using Unix Sessions: Tue, Aug 30, 4-5pm Wed, Aug 31 8-9pm (Sep 01)	Introduction to Python and Unix Zelle Chapt. 1-2 Useful Unix commands Getting started with python and Unix	lab 0: lab 0 In class:Wed & Fri lab 1: lab 1
2	Sep 05	Quiz 1 in class Friday Quiz 1 Study Guide add/drop ends (Sep 09)	Numbers and Strings Chapt. 3, 4.1, 4.2 (optional: string formating 4.5.2)	In class: Mon,Wed,Fri Assn:lab 2
3	Sep 12		if/else Booleans Chapt. 7.1, 7.2, 7.3, 8.4.1 p. 246-247, 8.4.2 (DeMorgan's Laws)	In class: Mon,Wed In class:Fri Assn:lab 3
4	Sep 19	Quiz 2 in class Friday Quiz 2 Study Guide (Sep 23)	Graphics, objects Chapt. 5 (skip 5.5, 5.6) notes on the Graphics Library	In class: Mon, Wed In class:Fri Assn:lab 4
5	Sep 26		Functions, Objects Chapt. 6 (skip 6.3)	In class: week 5 Assn:lab 5 Assn:lab 5 written part
6	Oct 03	Quiz 3 Quiz 3 Study Guide (Oct 07)	while Loops, More Functions Notes on strings and lists as objects Notes on using the random library Chapt. 8.1, 8.2, 8.3, 4.4.1, 4.3	In class: week 6 Assn:lab 6
	Oct 10	Fall Break
7	Oct 17		Top Down Design, File I/O Notes on strings and lists as objects Notes on using the random library Chapt. 9.1, 9.2, 9.3	In class: Mon WedFri: Top Down Design Assn:lab 7
8	Oct 24		More Top Down Design, File I/O Chapt. 9.1, 9.2, 9.3, 4.6 notes on File I/O	In class: Mon In class: Wed Fri Assn:lab 8
9	Oct 31	Quiz 4 Quiz 4 Study Guide (Nov 04)	Searching, Analysis of Algorithms Chapt. 13.1	In class: week 9 Assn:lab 9
10	Nov 07		Sorting, Analysis of Algorithms Ch. 13.2-13.3	In class: week 10 In class: Wed Assn:lab 10
11	Nov 14	Quiz 5 Quiz 5 Study Guide (Nov 18)	Recursion Chapt. 13.1-13.3	In class: Mon In class: Wed, Fri Assn:lab 11
12	Nov 21	Thanksgiving break (Nov 25)	Defining new classes and Linked Lists Chapt. 10.1, 10.3, 10.4 handout	In class: Mon In class:Wed
13	Nov 28		Linked lists handout	In class: week 13 Assn:lab 12
14	Dec 05	Final Exam Study Guide	Wrap-up
	Dec 15	Final Exam (7pm-10pm) room 101 Sci Ctr

External Links

Links that are related to the course may be posted here. If you have suggestions for links, let me know.

• Getting started with python and Unix
• running update21 and handin21
• Useful Unix commands
• vim reference
• My Unix Documentation editors, email, protecting/sharing files, Python programming guide, ...
• CS dept. help pages (that includes the Using Unix Tutorial)

• Python Code Style Guide
• Python Links
• Python Tutorial from python.org This tutorial covers some parts of the python language that we will not cover in class, so use this as a reference for the parts we do cover and don't worry about the parts we don't. Also, if you start out at the python.org website, make sure that you look at reference material for version 2.X or 2.6 of python (this is the version we are using).