> implementing your own linked list or using recursion I believe I can salvage this piece of the comment, and make it into an intelligent thing to say. Implem

> implementing your own linked list or using recursion I believe I can salvage this piece of the comment, and make it into an intelligent thing to say. Implementing your own linked lists? Not good unless your language is stone-knives-and-bear-skins land. You need to know what libraries are out there and available to you, and if CS undergrad stuff is unknown to the libraries in your language, pick a different one if you possibly can. Recursion is an important skill, but implementing your own recursive functions is low-level. It's error-prone and it's boring in precisely the ways that cause errors. Implementing your own map function is worse than implementing your own linked lists; it's more like implementing your own while loops out of labels and goto statements. It's an invitation to have bugs in your program's flow control, which is the worst possible place for them to be. Sometimes you need to write your own recursive function, because none of the basic recursive patterns your libraries give you can fit. Sometimes you need to implement your own foundational data structures, too. Both of these should be done with skepticism, primarily of your own code, but also of the very idea that you'd actually need to do it in the first place.