What are the important notions in C that you did not learn from your teachers? [closed]

Answer 1

How about general best practices?

• Always assume that someone else has already written your code and that it is both freely available on the internet and better written and tested than anything you'll produce before your deadline.
• Return early / Avoid else clauses
• Initialize all variables
• One page per function as a guideline (i.e. Use smaller pieces of code together)
• When to use switch, if-else if, or a hash table
• Avoid global variables
• Always check your inputs and your outputs (I don't trust my own code.)

• Most functions should return a status

  [ To others: feel free to edit this and add to the list ]

Regarding checking inputs:

I once wrote a big program in a hurry and I wrote all kinds of Guard Clauses, input checks, into my functions. When I ran the program for the first time, the errors from those clauses streamed by so fast I couldn't even read them, but the program did not crash and could be shut down cleanly. It was then a simple matter of going through the list and fixing bugs which went surprisingly fast.

Think of Guard Clauses as run-time compiler warnings and errors.