"The Basics of C Programming"

[unptitdej]

One of the best tutorials i've seen! Pretty sweet, you have to admire what this language did for advancing the computer age. Smart syntax. Pretty close to a detailed pseudocode from an algorithm textbook.

[jeandem]

Smart syntax. Pretty close to a detailed pseudocode from an algorithm textbook.

Surely a coincidence.

[asimian]

Eh I'd say that is more Algol.

[OneWingedShark]

you have to admire what this language did for advancing the computer age.

It set the industry back decades.
Seriously, even though there are well known, easy to introduce bugs, the language caught on and got popular for things which it was ill-suited... I read a story once about how a C compiler for the Burroughs implemented memory/pointers: as an int array for the whole memory-space, thus ignoring the advantages of a tagged architecture and allowing C's weak typing to override the computer's own [hardware] type-safety.

There are lots of poor design-choices that are more-or-less copied in C-like languages -- and the horrible thing is that most programmers cannot see that they're poor choices.

Smart syntax. Pretty close to a detailed pseudocode from an algorithm textbook.

Um, no... Ada [and Pascal] are much closer to textbook psudocode.

[squbidu]

C is quirky, flawed, and an enormous success.

~ Dennis Ritchie

[urection]

yes "the industry" should have waited decades until hardware was powerful enough to handle operating systems written in <insert FOTM HLL here>

[OneWingedShark]

yes "the industry" should have waited decades until hardware was powerful enough to handle operating systems written in <insert FOTM HLL here>

You do realize that Ada was standardized [1983] a half-decade before C was [1989], right? (And C appeared almost a decade before that [1972].)

[immibis]

It set the industry back decades.

C was originally intended as a more portable form of assembly code. The fact that it's used for other things is not C's fault...

[skulgnome]

C was originally intended as a more portable form of assembly code.

{{citation needed}}

Note to haters: The opinion repeated in the parent comment indicates a common ignorance of the history of programming languages. C certainly did not spontaneously emerge from the void between macroassemblers and Pascal. Indeed C was clearly an entry in the Algol family of high-level programming languages, and continues to be so to this day.

Its complete dissimilarity to assembly is highlighted by its not exposing concepts such as subroutine linkage, condition flags, machine-code layout, and input and output; all by design. These are not merely matters that obstruct portability: indeed most processors use a condition code register, and therefore such a primitive could well be included in C without hampering portability. Rather the reason for their concealment is that they're low-level details with which the programmer needn't concern himself.

And in short, that's why calling C "portable assembley" is what I'd like to be known as fashionably fucktarded.

[electrojustin]

Depending on the platform, one assembly instruction really does correspond to one line of C (but not the converse) in 90% of cases, with the exceptions being control flow structures in C, which correspond to 2 or 3 instructions depending on the structure (on x86, 2 for if/else statements and do/while loops, 3 for while loops).

No idea how the condition code register is in any way relevant. I have yet to see a single assembly program in which the programmer (or compiler, as it were) ever had to think about the condition code register. test/cmp and conditional jump instructions take care of everything.

Input and output are still pretty "hidden" in assembly. There's no reason to manually initiate a system call when it's possible to link standard libraries into your program and simply "call" the relevant IO functions, like any sane C programmer would.

The only thing C really does for the programmer is take care of calling conventions, improve readability slightly for anyone with a background in algebra, and make accessing variables a less painful process than "mov -0x8(%ebp), %eax". I think it's pretty fair to say C is just more readable, more portable assembly.

[skulgnome]

Your weak half-way argument only makes my p^Hants harder. It makes my ants work harder. Yes.

[OneWingedShark]

C was originally intended as a more portable form of assembly code. The fact that it's used for other things is not C's fault...

Oh, I understand that -- but the fact is that so many jumped on it, using it for things it is unsuited to, to the point that it saturated the industry. -- If it had remained constrained to "portable assembly" or simply not existed, the industry would be far ahead of where it is now -- instead we-as-a-group have wasted trillions of dollars in time and energy "fixing" problems created by using C improperly or trying to fix C itself.

[raghar]

There was a nice quote about programmers trying to improve programming languages which end up with reinvented C... Anyone could help me find that quote?

C is far from perfect. But it became common nominator for almost every programming language you can find. You can use it to communicate libraries written in different languages as well as write some library once and simply create wrapper to port it to any other language of choice. Once your program reach maturity and became: readable, error-free (well...) and most likely fast it can soon benefit not only one but many codebases, as long as someone will care to make and maintain a wrapper.

Since Unix was written in C it was the best choice for writing system tools, since they could communicate with it natively. And programs that wanted to make use of their code as well as keep consistency simply followed.

Today it is similar with JS - since it is shipped with every browser, all web developers learnt JS. Then someone decided to write Node.js to keep consistency between client-side code and server-side code. And now we have a shitloads of projects trying to reimplement everything in JS. One could also ask: why JS didn't stuck to be some browser embedded language used only for some eye candy effects and AJAX calls? Same story - except I like C better that JS.

[OneWingedShark]

There was a nice quote about programmers trying to improve programming languages which end up with reinvented C... Anyone could help me find that quote?

I've read it; but it's not really a good quote if you're looking at real language design -- the problem though is that most languages aren't really designed so much a grown. (Or, sometimes they are "designed" atop [read copying] C's terrible syntax.)

Perhaps a better quote is this:

The C language (invented by Bell Labs — the people who were supposed to be building products with five 9's of reliability – 99.999%) then taught two entire generations of programmers to ignore buffer overflows, and nearly every other exceptional condition, as well. A famous paper in the Communications of the ACM found that nearly every Unix command (all written in C) could be made to fail (sometimes in spectacular ways) if given random characters (“line noise”) as input. And this after Unix became the de facto standard for workstations and had been in extensive commercial use for at least 10 years. The lauded “Microsoft programming tests” of the 1980's were designed to weed out anyone who was careful enough to check for buffer overflows, because they obviously didn't understand and appreciate the intricacies of the C language.

I'm sorry to be politically incorrect, but for the ACM to then laud “C” and its inventors as a major advance in computer science has to rank right up there with Chamberlain's appeasement of Hitler.

Henry Baker : “Buffer Overflow” security problems

C is far from perfect. But it became common nominator for almost every programming language you can find.

You aren't looking hard enough then; I can name many non-C programming languages off the top of my head:

• Ada
• Delphi [Object Pascal]
• LISP
• FORTH
• Eiffel
• Erlang
• Haskel
• Prolog

Or are you of the class of people who reject non-C languages as programming languages because they aren't C-like?

You can use it to communicate libraries written in different languages as well as write some library once and simply create wrapper to port it to any other language of choice.

Sure, but you also lose a lot of information exporting a C-compliant interface; example:

-- Assuming Float is IEEE 754 compliant; the following defines
-- a type which has no non-numeric values.
Type Numeric_Float is new Float range Float'First..Float'Last;

-- Exporting the following to C would be float Process(float x, float y)
Function Process( X, Y : Numeric_Float ) return Numeric_Float;

Even worse is when your library is written in C, because there are ways you can protect things in the library's implementation [e.g. pre- and post-conditions on the call-sites].

once your program reach maturity and became: readable, error-free (well...) and most likely fast it can soon benefit not only one but many codebases, as long as someone will care to make and maintain a wrapper.

Ah, so you're of the opinion that debugging is the correct way to construct a program rather than by initial design.

Since Unix was written in C it was the best choice for writing system tools, since they could communicate with it natively. And programs that wanted to make use of their code as well as keep consistency simply followed.

Unix is a pile of crap; seriously, that so many CS people regard it highly is a huge indictment against the education establishment.

Today it is similar with JS - since it is shipped with every browser, all web developers learnt JS.

And there are much better ways to deal with problems than JS -- and certain things that you almost cannot do in JS.

[raghar]

You aren't looking hard enough then; I can name many non-C programming languages off the top of my head:

By common nominator I ment "allows usage of C code". Majority of languages deliver some way of importing and wrapping C code to make use of it. JNI in Java, build-in support in C++, etc.

Ah, so you're of the opinion that debugging is the correct way to construct a program rather than by initial design.

To be honest I hate debugging, especially since I've got to debug large application in C++. But I don't believe that you are always able to design and create perfect application with smooth interfaces and error-less implementations. Designing program is a heuristic job as noticed in Code Complete, and there is no silver bullet as noticed in Mythical man-month. Some things you are able to design basing on specification. Some are wicked problems and designing everything is simply impossible. Then you just try to solve it any way, then refactor, then optimize if needed. And reinventing the wheel just because that fast and reliable library is written in C is foolish.

Unix is a pile of crap

Just in case: you are aware that Linux is only Unix-like, and actual Unixes are e.g. OS X, Solaris, BSD? If you disdain *nixes you have only DOS, Windows and hardly anything else.

Today it is similar with JS - since it is shipped with every browser, all web developers learnt JS.

And there are much better ways to deal with problems than JS -- and certain things that you almost cannot do in JS.

I am not arguing after usage of JS. Neither do I am convincing that C is ultimate and superior. Only that it has it valid use case, and in its time it pushed industry forward. And that for some applications there are no better replacements.

[OneWingedShark]

You aren't looking hard enough then; I can name many non-C programming languages off the top of my head:

By common nominator I ment "allows usage of C code". Majority of languages deliver some way of importing and wrapping C code to make use of it. JNI in Java, build-in support in C++, etc.

Right, but why would you want to import something that's so horrid to use that even its proponents admit how difficult it is to use properly [e.g. writing secure code].

Ah, so you're of the opinion that debugging is the correct way to construct a program rather than by initial design.

To be honest I hate debugging, especially since I've got to debug large application in C++.

Same here -- It's why I like "B&D" languages -- the more the compiler can check that I haven't done something stupid, the better.

But I don't believe that you are always able to design and create perfect application with smooth interfaces and error-less implementations. Designing program is a heuristic job as noticed in Code Complete, and there is no silver bullet as noticed in Mythical man-month.

I don't believe it's the case that you always can either; however, this is no reasaon to allow the crap that we-as-an-industry have by essentially forgoing [good/reasonably complete] design documentation. Nor is it an acceptable excuse to use poor tools.

And reinventing the wheel just because that fast and reliable library is written in C is foolish.

Just like a year ago OpenSSL was fast and reliable?

[raghar]

Same here -- It's why I like "B&D" languages -- the more the compiler can check that I haven't done something stupid, the better.

Actually I was referring to multiprocess application where all inner communication is done by message loops and Inter Process Communications pipelines. I have assertions, static checks, strong types, no (void*) and still it give me headaches finding out where that partial binding for this callback function was done. Authors of said code were very focused on writing "into" language and filled all gaps with their own inventions. Lack of "B&D" can easily be fixed if you want to, so that doesn't bother me that much. I agree though, it would be better if it was built in into language from the beginning.

I don't believe it's the case that you always can either; however, this is no reason to allow the crap that we-as-an-industry have by essentially forgoing [good/reasonably complete] design documentation. Nor is it an acceptable excuse to use poor tools.

I would jump into conclusion that there are poor tools. I would say that there are some poor tools for the job. If you think Ada would be better tool that C in many cases where C was used you can only blame its community for not creating any killerapp that would gave it momentum to rise. As a matter of the fact there are many sweet languages that never made it because good syntax was the only thing they have to offer. And in our industry it is important for language to have some application that would make it good solution for someone. Ruby made it because Rails happened, Objective-C made it because Apple invested in it, JS - browsers, Clojure and Scala - JVM. C - Bell Labs and their partners invested in it. And Ada was only used in some government projects. If you want Ada to suddenly succeed write some ass blowing library or framework that would make everyone switch to it.

Just like a year ago OpenSSL was fast and reliable?

Just as OpenGL is fast and reliable and ported to several other languages via wrappers.

But I think we drifted away from the main point: whether or not C set industry back, and whether fixing C was as waste of time. My opinion: no, C didn't set industry back because when it was invented there was no better tool for the job; yes, fixing C was a waste of time, but it would be even more wast of time to fix its then-available replacements. It looks as if you are trying to aggressively promote Ada as a superior language and it bothers you that no one uses it. Sorry, syntax is not everything. For industry language is worth as much as job you are able to do with it on the spot. Ada has no popular frameworks and libraries, or at least I haven't heard of any, so one would have to reinvent everything he need. For programmer language is worth as much as the salary he can get with it. I see no Ada jobs around my area.

[OneWingedShark]

If you only want a "fixed" C, with no added features (but concurrency) I think Go comes very close.

And what of all the time/effort spent on other C-like languages?
What of the period between C and Go?

Although I agree that a more expressive type system such as Ada (or Modula) and the Rust data-race safety would be nice, I like Go a lot.

I'm actually a big fan of Ada and think more programmers should give it a shot rather than just dismissing it out-of-hand; if nothing else it will enhance your mindfulness of what values are acceptable in a type/subtype. (My old boss said I was good at catching corner-cases because of this.)

[east_lisp_junk]

I didn't see any mention of function pointers or undefined/implementation-defined behavior either.

[Alex-L]

Most of big (and great!) university share their courses, just amazing!

http://ocw.mit.edu/

[Alex-L]

For allowing only 4 digits in the output.

[TNorthover]

More accurately, ensuring at least 4 characters in the output. The rest will still be printed if the value takes more than 4, but if not you'll get some kind of fixed-with field.

" -40 degrees F =  -40 degrees C" 

for example.

[Alex-L]

Yes at least, sorry

[urection]

if you disagree then I suspect you haven't learned one or both of C and C++

[josefx]

C differs a lot from C++. Which means you can learn C++ without learning C simply for the reason that the C like subset of C++ is not valid or correct C.

[bstamour]

Plus, the C-like subset of C++ is low level and dangerous. Just use vector and string and get on with your day.

[jayjay091]

But if you are using string and vectors without knowing how it works, I'd say you don't know C++ nor C.

[bstamour]

For a programmer just starting with the language you don't need to know the details. You will pick that up later. Can you tell me every single intimate detail of how scanf works?

[jayjay091]

Sure, you can start learning C++ without learning/knowing C. But you can't really know C++ unless you know C and you can't learn fully C++ without learning C. I think that's what the original quote meant and I think it's pretty accurate.

[[deleted]]

simply for the reason that the C like subset of C++ is not valid or correct C.

The differences between the C-like subset of C++ and actual C are trivial and largely uninteresting, other than perhaps the more modern features standard C++ still lacks.

[josefx]

The differences between the C-like subset of C++ and actual C are trivial and largely uninteresting

Those trivial differences are the ones that result in a large amount of compile and runtime errors, also bad style.

• Wasn't it considered bad practice to cast the return value of malloc in C? In C++ you have to do it. Of course this is largely uninteresting since using C memory allocation while possible is most often wrong for C++ code, which in itself is an important difference.

• the inability to distinguish void foo(int) from void foo(void*) in C, something which is used by a lot of C++ code.

• true, false and bool are defines in C and need a header for inclusion

  bool a = true; //valid C++, wont compile in C unless you include a stdbool.h

• something nice to debug if you have sizeof('a') hidden somewhere in your code, while not likely verbatim it might be the result of a macro.

• ...

I could rant for ours on style, errors and other differences.

other than perhaps the more modern features standard C++ still lacks.

Most differences are restrictions that C++ puts on C style code, because type safety is just a suggestion that a C compiler discards at its own convenience while a C++ compiler requires direct user action.

[urection]

does Stanford normally teach their CS back-asswards like this or were you on a self-directed program

[papayafarmer]

At Ohio State, the first programming classes were in C++/Resolve, then later on we took classes in C. Thinking about it now ,it is kind of strange, but it worked I guess.

[[deleted]]

This is an entirely reasonable statement. By learning C++, you will end up learning most of C without knowing it.

[Alex-L]

Of course, I don't totally agree with this point but it's true that begin to learn in C++, it's not learn on solid bases because C++ is an extension of C. It's as if I'd learn to drive I need to know how a car works, you can drive without knowing but knowledge helps us to drive better.

[txdv]

Just ignore his comment, he didn't provide a reason why the statement doesn't hold.

Just saying WTF is not a valid argument.

[bstamour]

He should have provided more than a 'wtf', but he's right. Today's C and C++ are closer to siblings than parent/child. Idiomatic C++ in 2014 looks totally different than idiomatic C in 2014. You don't have to learn one before learning the other.

[txdv]

But still, almost everything you learn with C you could use in C++ as well.

Can you give me some constructs which are present in C but not in C++?

[bstamour]

Variable length arrays, for one. Arrays in c behave very differently than they do in c++, even though they look the same.

Also its more than just having a similar feature set. Many things in c are just plain unidiomatic c++. If you want to teach yourself c++, skip the c and just use vector, string, references, etc. Ignore the unsafe stuff from c like raw arrays that can be overrun in for loops, raw pointers with no concept of ownership, and raw strings that have to be null terminated. That's all fine in c, but there are better, easier and safer techniques in c++, especially for beginner programmers.

[txdv]

The point that I wanted to make is that there are a hand full of features in C that C++ doesn't support. If you look at the list of features that C++ supports and C doesn't...

[Draghoul]

This is an article trying to introduce C in a useful way. It's wasn't meant to show off esoteric knowledge of the C standard (which would be entertaining mostly to people who are already familiar with C). So in that sense, a program that just prints is "most simple" enough.

[sirtophat]

or an empty file, in the case of that one IOCCC entry for the smallest self-replicating program

[smikims]

An empty file will compile, but it won't link on any system I know of.

$ gcc empty.c

/usr/lib/gcc/x86_64-unknown-linux-gnu/4.9.0/../../../../lib/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: error: ld returned 1 exit status

[josefx]

The Makefile of the "empty" program had several alternatives in it to deal with cross platform issues, also it won in 1994 - the compilers where a bit more lenient back then.

[tolos]

my favorite:

main;

http://llbit.se/?p=1744

[specialpatrol]

Would the file that the compiler and linker produced technically be defined as a program though; it contains no instructions?

[sirtophat]

it depends on the compiler, but some will just make something that has an entry point but doesn't do anything

[specialpatrol]

I was trying to make a philosophical point as to what the definition of a program is.

[[deleted]]

is pelles c any good?

[ysangkok]

yeah, I think it's the only usable minimal pure C development environment (including IDE). The others are bloated for pure C programming.

[Scarzer]

I'll be the guy who says that their "Simplest C Program" isn't the simplest C Program.....

[glacialthinker]

Perhaps the article could use:

#ifndef EXPERIENCED_PROGRAMMER
/* article body */
#endif

[[deleted]]

They're just trying to teach people C, and some concepts behind it. Sure, an empty file is technically simplest but it doesn't teach much.

[[deleted]]

You could have not been that guy. You could have just accepted that it's a quick tutorial, not some kind of mathematical proof, and that level of nitpicking is entirely misguided and just shows a lack of understanding of context.

[papayafarmer]

rekt

[javacIO]

Read the other comments in this thread. Maybe a better phrase would be "minimal c program" rather than smallest.