List of stackoverflow.com answers I might need again

This is a list of stackoverflow.com answers that I have made, and that I might need to reference some time in the future.

• Structures that involve linked list and pointers : http://stackoverflow.com/a/13758104/440558
  This answer is showing layout of a single-linked list, with a head and tail pointer.
• GCC: Use OpenSSL’s SHA256 Functions : http://stackoverflow.com/a/13784484/440558
  The question is about undefined references when linking, and the answer is to put libraries last on the command line.
• C++ class member callback simple examples : http://stackoverflow.com/a/14189561/440558
  The question is about callbacks in classes, I made an answer showing the use of std::function and std::bind.
• Issue when scheduling tasks using clock() function : http://stackoverflow.com/a/11866539/440558
  I made some simple timer event handling.
• Error reading many files in a subfolder : http://stackoverflow.com/a/15251903/440558
  A function to recurse through directories using opendir and readdir.
• Text Wrapping in C on Thermo Mini Printer : http://stackoverflow.com/a/15720061/440558
  Example program how to do simple word-wrap.
• casting void** to 2D array of int – C: http://stackoverflow.com/a/18440456/440558 Contains simple ASCII-art diagrams to show the difference between a matrix using array-of-array and a matrix using pointer-to-pointer.

A list of other answers that might be useful:

• What’s the best way to trim std::string : http://stackoverflow.com/a/217605/440558
  This answer contains a set of functions to trim a std::string
• How to map between a matrix and an array
• Passing a multidimensional variable length array to a function

This isn’t an answer per-se, instead it’s intended as a comment for new users who post inappropriate questions:

• First part

Welcome to stackoverflow.com. Please take some time to read [the help pages](http://stackoverflow.com/help), especially the sections named ["What topics can I ask about here?"](http://stackoverflow.com/help/on-topic) and ["What types of questions should I avoid asking?"](http://stackoverflow.com/help/dont-ask). Also please [take the tour](http://stackoverflow.com/tour) and [read about how to ask good questions](http://stackoverflow.com/help/how-to-ask). Lastly please learn how to create a [Minimal, Complete, and Verifiable Example](http://stackoverflow.com/help/mcve).

• Second part

Also please read [this question checklist](https://codeblog.jonskeet.uk/2012/11/24/stack-overflow-question-checklist/), and all of http://idownvotedbecau.se/ to learn some reasons your question might be down-voted. Finally, please [learn how to debug your programs](https://ericlippert.com/2014/03/05/how-to-debug-small-programs/).