What is the convention about describing the direction of the stack, i.e., about what the words up, down, top, and bottom mean?
I noticed that with stack data structure API, top usually to refer to the most recently added item. I never saw high level language or library documentation refer to the newly added item in the stack as anything other than "top".
On the other hand, discussions about the program call stack often use the opposite convention, referring for example to the exceptions propagating up the stack (from the currently executing function towards the main function). Does the convention vary depending on the language, or some other factor?
To clarify: my question is only about the usage in the context of high-level language programming – not the direction in which the CPU/OS grows stack in physical memory (which varies by platform).
Best Answer
You
pushitems onto andpopthem off of the top of the stack, regardless of how it is laid out in memory.The stack terminology is intended to mirror a physical stack (of plates, in particular):
As it pertains to exceptions, strictly speaking, an exception propagates down the stack, from the most recently called function to the least recently called function. Google "exception propagation," and one of the first few results shows it like this:
However, when someone says "propagates up the stack," we understand what they mean. So, we don't fuss over it. Whether it's up or down in their heads isn't as relevant as whether they ultimately mean "most recent" to "least recent" (or "in opposite order of invocation").