• The final exam study guide is posted
  • Lab 12 is posted, due Wednesday, December 7 at 11:59pm.
  • Reminder: the final exam will be given December 15 from 7pm-10pm in 101 Sci Ctr
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: TR 1:15–2:30pm, Science Center 240
Professor: Ameet Soni
Office hours: 2:30-3:30pm Fridays, and by appointment, Room 253

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:

Goals for the course:

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

Student Support

Student Support Coordinator: Darla Henning (office: 257 Sci Ctr phone: x6062)
CS21 Ninjas (student mentors): Sarah Chasins, Stella Cho, Steven Hwang, Joan 0'Bryan, Mark Serrano, Brandon Snuggs

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 7-9pm 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 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.

Time Professor Location
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 240

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 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

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.


Grades will be weighted as follows:
40%Lab assignments
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 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 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. 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.


This is a tentative schedule; it may change as we go.
1 Aug 30 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: Tuesday
Assn: lab 0
In class: Thursday
Assn: lab 1
Sep 01  
2 Sep 06 Quiz 1 Study Info Numbers and Strings
Chapt. 3, 4.1, 4.2
In class: Tuesday, Thursday
Assn: lab 2
Sep 08 Quiz 1
add/drop ends (Sep 09)
3 Sep 13   if/else Booleans
Chapt. 7.1, 7.2, 7.3 and 8.4.1, 8.4.2
In class: Tuesday
Assn: lab 3
Sep 15  
4 Sep 20 Quiz 2 Study Info Graphics, objects
Chapt. 5 (skip 5.5, 5.6)
notes on the Graphics Library
In class: Tuesday, Thursday
Assn: lab 4
Sep 22 Quiz 2
5 Sep 27   Functions, Objects
Chapt. 6 (skip 6.3)
In class: Tuesday, Thursday
Assn: lab 5
Assn: lab 5 written portion
Assn: Quiz 2 re-try
Sep 29  
6 Oct 04 Quiz 3 Study Info 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
Assn: lab 6
In class: Thursday
Oct 06 Quiz 3

Oct 11

Fall Break

Oct 13

7 Oct 18   Top Down Design, File I/O
Chapt. 9.1, 9.2, 9.3, 4.6
In class: Tuesday
In class: Thursday
Assn: lab 7
Oct 20  
8 Oct 25   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 8
Oct 27  
9 Nov 01 Quiz 4 Study Info Searching, Analysis of Algorithms
Chapt. 13.1
In class: Tuesday, Thursday
Assn: lab 9
Nov 03 Quiz 4
10 Nov 08   Sorting, Analysis of Algorithms
Ch. 13.2-13.3
In class: Tuesday, Thursday
Assn: lab 10
Assn: lab 10 worksheet
Nov 10  
11 Nov 15 Quiz 5 Study Info Recursion
Chapt. 13.1-13.3
In class:
Assn: lab 11
Nov 17 Quiz 5
12 Nov 22   Defining new classes and Linked Lists
Chapt. 10.1, 10.3, 10.4
In class:
Nov 24 Thanksgiving break
13 Nov 29   Linked lists
In class:
Assn: lab 12
Dec 01  
14 Dec 06 Final Exam Study Guide Wrap-up

Dec 15

Final Exam (7pm-10pm) room 101 Sci Ctr

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