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while loop

We return to the topic of iteration! A while loop allows us to deal with indefinite iteration--iterating an unknown (or not easily knowable) number of times until some stopping condition is reached.

Slides for all 3 videos of this lecture: individual slides for viewing and a "6-up" version for printing.

The answers to the questions asked during this lecture are in a separate file at the end of this page.

Part 1: Indefinite iteration, syntax, and flow

When do we use a while loop? When we deal with indefinite iteration. We learn what is indefinite iteration and the syntax and flow of the while loop.

• video
• audio only
• Code: euclid.py, guessNumber.py

Part 2: Choose while or for?

How could we choose between the two kinds of loops? We look at some examples and discuss the advantages and disadvantages of using while.

• video
• audio only

Part 3: How to set up a while loop?

We suggest some steps for setting up a while loop and use them to write a number guessing game. Try writing your own version as well! There are different ways to set up a while loop for the game.

• video
• audio only
• Starter code: guessNumberSkeleton.py. Completed game: guessNumberLimitGuesses.py

Answers to the questions asked during lecture: pdf