For developers who learn by struggling
The last time you chose a new framework or library, was it because your problem needed that tool, or because it sounded cool and few people around you were using it? That question is uncomfortable. Technology decisions are often made for reasons that never appear in any technical document.
A linked list is a linear chain of nodes, each holding data and a pointer to the next node. Here is what that chain looks like, what it costs next to an array, and the same minimal implementation in Java, Python, and JavaScript.
An algorithm is an ordered list of steps, and that order decides how expensive a problem is. The examples are on the back of an instant noodle packet, in a factorial, and behind ctrl+z.
Four prices add up to 47000, and the cart program prints 36500. The bound is prices.length - 1, so the last item is never read while the average is still divided by four.
A grading program marks a paper 78 and prints grade: C. case 7 assigns B and then runs into case 6 because the break is missing, and the compiler says nothing about it.