> For the complete documentation index, see [llms.txt](https://hanfak.gitbook.io/workspace/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hanfak.gitbook.io/workspace/general/logic.md).

# Logic

* the basic code you learn to write when you start programming
* Consists of
  * control statements, in this case REPEAT-UNTIL for a loop. Other statements are if-else, switch-case, while, for, foreach... or what your programming language is offering you in the same vein.
  * I/O or more generally "API-calls", i.e. calls to libraries you choose to base your code on
    * you don't have control over their source code. For all practical matters they are black boxes you're using as is.
  * transformations which range from mathematical operators to string operations or URL helper functions.
* what creates software behavior: functionality, performance, security, usability etc. It constitutes the gears in your software,
* Software behavior is what users observe and want to be useful for their purposes:
  * some input is transformed into some output, maybe by considering some state.
  * Software always has been and will be about IPO: input-process-output.
  * And logic is what accomplishes that feat.
* users want is programmers to produce appropriate logic.
* Logic alone is not enough. Writing just any logic in any way to deliver requested behavior is not enough
  * very quickly the amount of logic needs to grow beyond what a single human, let alone a team can handle without help.
  * might be sufficient in very small scenarios and when taking the first steps in programming.
  * principles and concepts are needed on how to structure logic with functions and modules (e.g. classes, libraries).
    * archtiecture and clean code etc
* First and foremost task of software developers is to compose code from logic building blocks in a way that it performs as required
  * shows useful behavior
* too much focus on just logic will be detrimental to the longterm productivity of a software developer.