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This syllabus is a living document; please be aware that many elements on this page will change throughout the semester, including the course schedule. It is the student's responsibility to review this page periodically for updates.

Class Info

Section 1: Tuesday, Thursday 9:55–11:10am, Science Center 240
Professor: Ameet Soni
email:
Office: Science Center, Rm 253 Office hours: 10:00-noon Monday, or by appointment

Welcome to CS21B. This course will introduce fundamental ideas in computer science while also teaching you how to write computer programs while exposing you to applications in biology. 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

Student Support Coordinator: Frances Ruiz (office: 257 Sci Ctr phone: x6062)
CS21 Ninjas (student mentors): Sarah Chasins and Leah Foster will be specifically assigned to our class (CS21B) and will be most able to help you with the lab assignments as well as with in-class problems. Other ninjas, helping all sections of CS21, include: Mark Serrano, Brandon Snuggs, Samantha Goldstein, and Sophie Libkind. These students can help you with general programming concepts and assist you in studying for quizzes.

Study sessions

The CS Ninjas will assist me in class and run study sessions in the main CS lab (Science Center 240) on the following evenings:

Day	Time	Location
Sundays	7-10pm	Sci Center 240
Wednesdays	7-9pm	Sci Center 240

You are invited -- and encouraged -- to participate in these 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.

Lab Sessions

CS21B will have a lab session every Monday from 2:40-4:10pm in Science Center 240. The CS lab is open 24 hours a day, 7 days a week for you to use for CS21 lab assignments. These lab sessions are designed to provide additional hands-on programming to understand lecture concepts as well as for assistance with weekly lab assignments.

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 this class

• 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.
• 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 Office of Student Disability Services.

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.

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.

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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 assignment policy

Programming assignments will typically be assigned Wednesday or Thursday of each week and will be due 11:59 pm, Tuesday the following week. 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 not be accepted except in extreme situations and only if you contact me at least a day before the deadline with a legitimate reason for needing extra time, such as an illness.

Even if you do not fully complete an assignment, you should submit what you have done to receive partial credit. Unless otherwise stated, labs are to be completed individually. Please carefully read the statement on academic integrity for more information.

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	Jan 17	Using Unix (240 SciCntr): Tue., 4-5pm Wed., 8-9pm	Introduction to Python and Unix Zelle Chapt. 1-2 Useful Unix commands Getting started with python and Unix	In class: Thursday Assn: Lab 0: Unix and vim Assn: Lab 1: Simple Programs
	Jan 19
2	Jan 24	Quiz 1 Study Guide	Numbers and Strings Chapt. 3, 4.1, 4.2	In class: Tuesday, Thursday Assn: Lab 2: Population Growth and Translation
	Jan 26	Quiz 1 add/drop ends (Jan 27)
3	Jan 31		if/else Booleans Chapt. 7.1, 7.2, 7.3 and 8.4.1, 8.4.2	In class: Tuesday, Thursday Assn: Lab 3: Transcription
	Feb 02
4	Feb 07	Quiz 2 Study Guide	Graphics, objects Chapt. 5 (skip 5.5, 5.6) notes on the Graphics Library	In class: Tuesday, Thursday Assn: Lab 4: Fun with Graphics
	Feb 09	Quiz 2
5	Feb 14		Functions, Objects Chapt. 6 (skip 6.3)	In class: Tuesday, Thursday Assn: Lab 5: Snail Race Assn: Worksheet
	Feb 16
6	Feb 21	Quiz 3 Study Guide	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	In class: Tuesday, Thursday Assn: Lab 6: Hardy Weinberg
	Feb 23	Quiz 3
7	Feb 28		Top Down Design, File I/O Chapt. 9.1, 9.2, 9.3, 4.6	In class: Tuesday
	Mar 01
	Mar 06	Spring Break
	Mar 08
8	Mar 13		More Top Down Design, File I/O Chapt. 9.1, 9.2, 9.3, 4.6 notes on File I/O	In class: Tuesday In class: Thursday Assn: Lab 7: Protein Alignment (Top Down Design)
	Mar 15
9	Mar 20	Quiz 4 Study Guide	Searching, Analysis of Algorithms Chapt. 13.1	In class: Tuesday, Thursday Assn: Lab 7: Protein Alignment (Implementation)
	Mar 22	Quiz 4
10	Mar 27		Sorting, Analysis of Algorithms Ch. 13.2-13.3	In class: Tuesday, Thursday Assn: Lab 8: Zipcodes Search & Sort worksheet
	Mar 29
11	Apr 03	Quiz 5 Study Guide	Recursion Chapt. 13.1-13.3	In class: Tuesday, Thursday Assn: Lab 9: Global Alignment
	Apr 05	Quiz 5
12	Apr 10		Defining New Classes Chapt. 10.1, 10.3, 10.4	In class: Tuesday, Thursday Assn: Lab 10: The Swindle
	Apr 12
13	Apr 17	Quiz 6 Study Guide	Linked lists handout	In class: Assn: Lab 11: Bacteria Colony
	Apr 19	Quiz 6
14	Apr 24		Wrap-up
	Apr 26	Final Exam Study Guide
	May 03	Final 7:00pm–10:00pm Sci 101

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: similar to handout from the first day of class.
• vim reference
• Prof. Newhall's 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).