Intro to Python for Computer Science and Data Science: Learning to Program with AI, Big Data and The Cloud

3.11 Program Development: Sentinel-Controlled Repetition

Let’s generalize the class-average problem. Consider the following requirements statement:

• Develop a class-averaging program that processes an arbitrary number of grades each time the program executes.

In the first class-average example, we knew in advance the 10 grades to process. The requirements statement does not state what the grades are or how many there are, so we’re going to have the user enter the grades into the program. The program processes an arbitrary number of grades. How can the program determine when to stop processing grades so that it can move on to calculate and display the class average?

One way to solve this problem is to use a special value called a sentinel value ...