> Take a Map or Dictionary for example. C doesn't technically speaking provide one, so you learn to implement them pretty quickly and often. I take issue with

> Take a Map or Dictionary for example. C doesn't technically speaking provide one, so you learn to implement them pretty quickly and often. I take issue with the "quickly and often" part, but you do learn to implement them! And that provides valuable insight when it comes to other languages. I've had senior devs who, like past me, didn't understand why removing an element from a vector or map invalidates iterators or indices on it. I learned precisely why when implementing vectors in C: the usual implementation of those collections shifts everything around to maintain element contiguity in memory, so now your iterator/index is pointing to a different element (which incrementation will skip) or possibly past all the elements! And when you're presented with these fancy data structures in Java or Python, that feels unintuitive and wrong. "Come on; I should be able to just iterate through this and remove certain elements as I go," like you would remove objects from a shelf. The shelf doesn't rearrange the objects after you take one out! But the reason it feels like an affront to common sense is that you've been trained to take the fancy data collections for granted and not forced to understand the complexity behind them that makes them efficient. Of course, the real answer is to do that with some functional algorithms, like `std::remove_if()`, instead of via iteration. That way, you'll really be in the cloud-scraping ivory tower and never have to think about what's going on below. https://youtu.be/ggijVDI6h_0 https://youtu.be/ggijVDI6h_0 :p