I haven't used hashtables or trees since I was in university, 15 years ago. I'd look them up if I needed them, but I never really have. Do people really keep these things in active memory?
If you're coding in a modern dynamic language, you're probably using hashtables every day without realizing it (that's one popular way dictionaries/associative arrays are implemented). As for trees, your code is a tree. Every time you're working with a nested data structure, you're working with a tree. Trees are fundamental to programming and data representation in a way hardly anything else is.
> As for trees, your code is a tree. Every time you're working with a nested data structure, you're working with a tree. Trees are fundamental to programming and data representation in a way hardly anything else is.
I haven't really needed to write a program to traverse my code as a tree, but I guess you're right that I must have used trees in C at some point.
