CS 115 Reading: Week 3

This page lists the skills you should have by the end of Week 3 and some suggested readings to help you get up to speed. How much you read is up to you.

Some of these sources discuss features of Python that we won't cover in class. You're welcome to use those features in your programs, but you will only be held responsible for material we actually cover in lectures, labs, and projects.

Definite loops

We started on these topics at the end of Week 2. By the end of Week 3, you should be very comfortable with:

• Using for loops to execute blocks of code repeatedly
• Tracing the sequence of values taken by a loop counter variable
• Using range to manipulate a loop counter

Suggested readings:

• Sections 2.6 and 2.7 of Zelle
• The Computer Science Circles section on loops (for- loops only)
• The following sections of Miller and Ranum. Note that they use for-loops to iterate through lists, which we'll get to a little bit later. For now, you only need to be able to write for-loops that use range:
  • Intro to the for-loop
  • Flow of execution of a for-loop, with a great flowchart
  • Explanation of the range function

Accumulations

By the end of Week 3, you should be able to trace the execution of code that uses accumulation. You should also be able to recognize simple examples of problems that use this pattern and write code to solve these problems.

Suggested readings:

• Video on using a loop to keep a running total (i.e. an accumulation)
• Sections 2.7, 3.3, and 8.1 of Zelle
• The section "The for-loop revisited" in Miller and Ranum
• The section on Newton's method in Miller and Ranum. This isn't easy reading, but if you truly understand this code, you're in GREAT shape. Save this one for last.

If-statements

By the end of Week 3, you should be comfortable tracing the execution of programs with if-statements, and you should be experimenting with writing code that makes decisions.

Suggested readings for the basics:

• Sections 7.1, 7.2, and 7.3 of Zelle
• The CS Circles section on if-statements, which also has a great guide to common error messages.
• The CS Circles section on else, and, or, and not.

Suggested readings to take it to the next level:

• The Miller and Ranum chapter on selection approaches the topic from a more theoretical perspective, starting with Boolean (True/False) and working up to if-statements.
• Section 7.5 of Zelle. This section emphasizes problem solving rather than syntax. This is important! Learning the details of a language can seem overwhelming at first, but experienced programmers will tell you that figuring out the steps in solving a problem is the real challenge in the long run.