• Final Exam Review Sessions Monday May 10 in CS lab: 10am-12pm, and 2pm-4pm
    You can attend either or both session. Come with questions for the professor to answer..
  • Ninja Final Exam Review Session: Sunday, May 9, 7-9pm

  • Final Exam Information content, format, tips for preparing and taking the final exam.
  • Final Exam (May 12, 7-10pm, room 101 Sci Cntr)

Class Info

Section 1: MWF 9:30–10:20, Sci Cntr 240
Professor: Tia Newhall
Office hours: 2-3 Weds, 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:

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: Betsy Horner (office: 257 Sci Ctr phone: x6062)

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
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 Meeden Science Center 240
1:00-2:00* Fridays 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 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

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.


Grades will be weighted as follows:
40%Homework assignments
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:

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. 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.


Reading Assignments are from the required Textbook:
1 Jan 18 Using Unix (240 SciCntr):
Tues: 4-5, Wed: 8-9pm
Introduction to Python and Unix
Chapt. 1-2
getting started guide: Python and Unix for lab assignments
In class: Mon
Assn: lab 0
In class:Wed,Fri

Assn:lab 1
2 Jan 25 Add/Drop ends Friday
practice Quiz 1
Numbers and Strings
Chapt. 3-4
In class: Mon, Wed,Fri
Assn: lab 2
3 Feb 01   Booleans
Ch. 7 and p. 247
In class: week3
Assn: lab 3
4 Feb 08 practice Quiz 2 Graphics, objects
Chap. 5
notes on the Graphics Library
In class: week 4
Assn: lab 4
5 Feb 15   Functions, objects
Chapt. 6
In class: week5
Assn: lab 5
6 Feb 22 practice Quiz 3 while Loops, More Functions
Notes on strings and lists as objects
Notes on using the random library
Chapt. 8
In class: week 6
Assn: lab 6
7 Mar 01   Top Down Design, File I/O
Chapt. 9, 4.6
notes on File I/O
In class: week 7

Mar 08

Spring Break

Mar 15   Searching, Analysis of Algorithms
Chapt. 13.1
In class: week 8
Assn: lab 7
9 Mar 22 practice Quiz 4 Sorting, Analysis of Algorithms
Ch. 13.2-13.3
notes on File I/O
In class: week 9
Assn: lab 8
10 Mar 29   Recursion
Chapt. 13.1-13.3
In class: week10
Assn: lab 9
11 Apr 05 practice Quiz 5 Defining new classes
Chapt. 10
In class: week 11
Assn: lab 10
12 Apr 12   Object Oriented Design
Chapt. 12
Linked lists handout
In class: week 12
Assn: lab 11
13 Apr 19 practice Quiz 6 Linked lists
In class: week 13
Assn: lab 12
14 Apr 26   Advanced Topics, Wrap-up In class: week 14

May 12

Final Exam (May 12, 7-10pm, room 101 Sci Cntr)

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