See this page.🕗 It contains instructions for each production that needs to be converted: From EBNF to BNF For building parsers (especially bottom-up) a BNF grammar is often better, than EBNF. But it’s easy to convert an EBNF Grammar to BNF: Convert every repetition { E } to a fresh non-terminal X and add X … Read more
I hope this qualifies as a programming question, as in any programming tutorial, you eventually come across ‘foo’ in the code examples. (yeah, right?) what does ‘foo’ really mean? If it is meant to mean nothing, when did it begin to be used so?
See my answer about spatial and temporal locality. In particular, arrays are contiguous memory blocks, so large chunks of them will be loaded into the cache upon first access. This makes it comparatively quick to access future elements of the array. Linked lists on the other hand aren’t necessarily in contiguous blocks of memory, and could … Read more
Because HTTP is stateless, in order to associate a request to any other request, you need a way to store user data between HTTP requests. Cookies or URL parameters ( for ex. like http://example.com/myPage?asd=lol&boo=no ) are both suitable ways to transport data between 2 or more request. However they are not good in case you don’t want … Read more
Why prefer composition over inheritance? What trade-offs are there for each approach? When should you choose inheritance over composition?
An invariant is more “conceptual” than a variable. In general, it’s a property of the program state that is always true. A function or method that ensures that the invariant holds is said to maintain the invariant. For instance, a binary search tree might have the invariant that for every node, the key of the … Read more
GUID technically stands for globally unique identifier. What it is, actually, is a 128 bit structure that is unlikely to ever repeat or create a collision. If you do the maths, the domain of values is in the undecillions. Use guids when you have multiple independent systems or clients generating ID’s that need to be unique. For example, … Read more
A library performs specific, well-defined operations. A framework is a skeleton where the application defines the “meat” of the operation by filling out the skeleton. The skeleton still has code to link up the parts but the most important work is done by the application. Examples of libraries: Network protocols, compression, image manipulation, string utilities, regular expression evaluation, math. Operations … Read more
The result of a modulo division is the remainder of an integer division of the given numbers. That means: Other examples:
Concurrency is when two or more tasks can start, run, and complete in overlapping time periods. It doesn’t necessarily mean they’ll ever both be running at the same instant. For example, multitasking on a single-core machine. Parallelism is when tasks literally run at the same time, e.g., on a multicore processor. Quoting Sun’s Multithreaded Programming Guide: Concurrency: A condition that exists when at least two … Read more