Lecture 20 Objectives

At the end of today's class you should

KNOW:

That a graph is a data structure formed of nodes and edges. There are many ways to implement graphs.
That to create data that contains cycles, you need to partially create the datum without the cycles, then use mutation to add the cycles. (We did this with DrRacket when we had mothers with children and children who had a mother.)
That programs might not terminate if the data they process contains loops.

BE ABLE TO:

Create examples of data that contain cycles

Sample Exam Question:

At the end of today's lecture, we found ourselves in an infinite loop related to the cycles in the graph data. In a sentence or two, suggest a way to prevent the infinite loop. (Hint: how did we prevent infinite loops in Racket when there were cycles in the data?)