Class Information

Room: Science Center 252
Class: Tuesday, Thursday 9:55–11:10pm
Professor: Lisa Meeden
Office: Science Center 243
Phone: 8565
Office hours: I will be available Wednesdays 2-4pm, or you can stop by whenever my door is open.

Welcome to CS21B. This course will introduce fundamental ideas in computer science and teach you how to write computer programs while exposing you to some 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
  (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: Betsy Horner (Office: Science Center 257, Phone: 6062)

CS21 Ninjas (student mentors): John Dinh, Christina Duron, Ivana Ng, Ashley Oudenne, Nick Rhinehart

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
Sunday	7-9pm	Sci Center 240
Wednesday	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 homework 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

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.

Day	Time	Professor	Location
Monday	2:30-4:00	Newhall	Science Center 240
Monday	3:30-5:00	Meeden	Science Center 240
Friday	1:00-2:00*	Turnbull	Science Center 240

* If there's a campus collection, the Friday lab will be 2-3pm in the overflow lab.

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.

Academic Accommodations

Academic accommodations are available for students with disabilities who are registered with Student Disability Services in the Dean's office. Students in need of disability accommodations should schedule an appointment with me early in the semester to discuss accommodations for this course that have been approved by the Dean's office. All requests must come through an accommodation letter from the Dean's office. To receive an accommodation for a course activity, your meeting with me must be at least one week prior to the activity.

Contact Tracey Rush at the Dean's office and follow these steps for obtaining accommodations.

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Grading

Grades will be weighted as follows:

40%	Homework assignments
30%	Quizzes
5%	Class Participation
25%	Final Exam

Homework policy

Programming 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 not be accepted except in extreme situations and only if you contact me before the deadline. 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

Academic Integrity

Academic honesty is required in all work you submit to be graded. With the exception of your lab partner on lab assignments, 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

WEEK	DAY	ANNOUNCEMENTS	TOPIC & READING	LABS
1	Jan 19		Introduction to Python and Unix Zelle chapters 1-2	Lab0 Lab1
	Jan 21
2	Jan 26		Numbers and Strings Zelle chapters 3-4	Lab2
	Jan 28	Quiz 1 Practice Quiz1 Drop/Add ends (Jan 29)
3	Feb 02		Booleans Zelle chapter 7 and pg. 247	Lab3
	Feb 04
4	Feb 09		Graphics, Objects Zelle chapter 5 Notes on the Graphics Library	Lab4
	Feb 11	Quiz 2 Practice Quiz2
5	Feb 16		Functions, Objects Zelle chapter 6	Lab5
	Feb 18
6	Feb 23		while Loops, More Functions Zelle chapter 8	Lab6
	Feb 25	Quiz 3 Practice Quiz3
7	Mar 02		Top Down Design, File I/O Zelle chapter 9, section 4.6	None
	Mar 04
	Mar 09	Spring Break
	Mar 11
8	Mar 16		Searching, Analysis of Algorithms Zelle section 13.1	Lab7
	Mar 18
9	Mar 23		Sorting, Analysis of Algorithms Zelle sections 13.2-13.3	Lab8
	Mar 25	Quiz 4 Practice Quiz4 Last day to declare CR/NC or W (Mar 26)
10	Mar 30		Recursion Zelle sections 13.1-13.3	Lab9
	Apr 01
11	Apr 06		Defining new classes Zelle chapter 10	Lab10
	Apr 08	Quiz 5 Practice Quiz5
12	Apr 13		Object Oriented Design Zelle chapter 12	Lab11
	Apr 15
13	Apr 20		Linked lists	Lab12
	Apr 22	Quiz 6 Practice Quiz6
14	Apr 27		Advanced Topics, Wrap-up
	Apr 29