CS173: Intro to Computer Science - Recursion
Activity Goals
The goals of this activity are:- To identify a recursive base case
- To implement recursive algorithms
Supplemental Reading
Feel free to visit these resources for supplemental background reading material.The Activity
Directions
Consider the activity models and answer the questions provided. First reflect on these questions on your own briefly, before discussing and comparing your thoughts with your group. Appoint one member of your group to discuss your findings with the class, and the rest of the group should help that member prepare their response. Answer each question individually from the activity, and compare with your group to prepare for our whole-class discussion. After class, think about the questions in the reflective prompt and respond to those individually in your notebook. Report out on areas of disagreement or items for which you and your group identified alternative approaches. Write down and report out questions you encountered along the way for group discussion.Model 1: Recursive Algorithms
Questions
- Notice that the algorithm "starts over" on a smaller part of the array after each guess. This is a hallmark of a "recursive algorithm." They are like loops. Do you think this approach requires more or less code to write than a non-recursive version? Why or why not?
- How many times did this algorithm compute
fib(2)
?
Model 2: Base Cases and Recursive Steps
Questions
- Fill in the base case and recusive call for the factorial function, and try running it!
Embedded Code Environment
You can try out some code examples in this embedded development environment! To share this with someone else, first have one member of your group make a small change to the file, then click "Open in Repl.it". Log into your Repl.it account (or create one if needed), and click the "Share" button at the top right. Note that some embedded Repl.it projects have multiple source files; you can see those by clicking the file icon on the left navigation bar of the embedded code frame. Share the link that opens up with your group members. Remember only to do this for partner/group activities!Reflective Journal Prompt
- How might you improve upon (reduce) the number of calls to
fib(2)
in the Fibonacci example?