When to use int, const int, const byte and Define

Hehe that's crazy. I'm guessing it wasn't work related, or the firm has serious questions to answer, how that passed a code review! 

Agreed.  A lot appear because they are just rehashes of prior examples that don't really explain, or at least only superficially, a particular problem by people being lazy or trying to appear clever.  Thus the incomplete explanations are forever propagated.  Where I've had to learn something new, I've done so with a very specific problem in mind to solve rather than following along blindly with foo and bar nonsense.  It helps of course to have the 10,000 hours under my belt so I can cross-relate principles and points.  And yet, C pointers......

And no, not work related per-se, just something tied to the museum that I've agreed to take on.  I've had to get to grips with PIC microprocessors and development and it was another egregious example of someone trying to be way too clever with their C code and unnecessary embedded assembler.  Although in fairness, he's a really nice chap and genuinely very, very clever so I don't think he realises!!

I'm fond of foo bar. It's part of it culture. One of the rare moments that there's some lightness in geek land. It also has a purpose: makes it very clear that a generic / abstract example is given. And recognisable by lovers and haters .

Other frequent visitors are hello, world!. And scott/tiger will bring warm memories to early Oracle developers. And the blinky.

shabaz said:

the firm has serious questions to answer, how that passed a code review! 

side story: I do code reviews in my company as volunteer. Usually when we have third-parties writing customisations for us.

I learn more than I find issues. Often, externals are certified developers. They are used to write code that will be reviewed. Most things that I send back are magic numbers, arbitrary maximums, and constructs that will cause sustain issues later.

I find the same too! It helps all parties to it. It's important for startups too, where there may be just one or two developers, it helps all if they use the remainder startup founders (who might not have done as much coding in the past) as their code reviewers, i.e. dragging anyone for a review (doesn't have to be heavily knowledgeable) it helps in that scenario, simply to speak through the design choices. The same applies for hardware reviews. 

 obones 

obones said:

#define NAME value tells the preprocessor to replace NAME by value wherever it sees it. It is just like copy/paste but done for you by the preprocessor, which means the compiler will never see the NAME item, only a repetition of value in lots of places

Sorry you don't get the star for this, you the  Penalty Box. "the #define" is a not copy and paste! It is a MACRO de-expansion tool. please see this example which I posted just before you did. " square #define sqr(a)  ((a)*(a)",  this is not copy and paste! just for giggles you can also do pi which is NOT in the Math lib you can do this:  #define pi 3.1416  kind of this and then nothing is correct you could use this: π=atan2(0,−1) now turn this into a 

#define  pi  atan2(0, -1)  

Cris.

I mess about with this thing. Its fast for running a test. but to get to work please use Eclipse with the GCC toolchain You'll, thank me. 

I have several of them one for C, one for Java and I have all of the embedded tools on a third. BTW I despise the Arduino IDE, (all I use is setup(), and then I write my own main() which Loop calls!!

I agree with you on Eclipse, GCC.

When we switch to the Arduino IDE, Setup(), Loop() and your code, I believe that the Arduino approach is better than what you are doing.

Yeah, you can do all kind of crazy stuff with the preprocessor, it's turing complete after all.

But for a "beginner's" explanation, seeing it a as copy/paste tool that replaces a given text by another one before sending it to the compiler is a much simpler way to grasp what it does.

And that also helps a lot understanding why the compiler will emit error messages that never mention the preprocessor symbol, which can be off putting when starting to work with this kind of concepts.

I don't agree, I taught K&R C on the side to students that had one semester. of Pascal. The two languages are very similar in construction ie semantically, even though one is a compiler, and the other is an interpreter. After getting to un-learn Pascals over the use of English to describe variables ( like fred_ponts_to_tom. the #derine though yes I start out with #define FAIL -1

but in the same had I also showed them things like a square which is #define SQR(a)  ((a)*(a)) and also pi see above and for pete sake hallway make your defines in UPPERCASE

If you try and learn a programing language you need to learn ALL of it. not some of it. 

btw what to make you Android programing easier?? don't use void loop()  as guess what void loop is a defined macro and invokes main()

which means now you can have return codes in main()   like int main( ){  return FAIL;}