Learn C The Hard Way

http://c.learncodethehardway.org/

by llambda • 15 years ago

220 49 15 years ago

c.learncodethehardway.org

I recently started working through Learn C the Hard Way, and after doing a few chapters I wrote down what I liked about it in a notebook. Digging it up, here it is:

"Why I like Learn C the Hard Way:

- Opinionated. I think opinionated textbooks are great because they limit their scope and focus on something. Rather than being an authoritative reference (who uses text references anymore?), it's a framework for learning.

- Emphasizes reading and editing which contributes to overall understanding

- It's lean. Goes with opinionated, but it's nice that it doesn't repeat what's been done, but sends you there directly, i.e. don't waste time writing about "strcmp", send me to "man 3 strcmp" since I need to get familiar with it anyway."

Disclaimer: I'm a bit new to low-level coding, so feel free to point out why these reasons for liking the text might be naiive.

oblique63• 15 years ago

I too just started reading this one.

For me, my first foray into 'low-level' programming was during my freshman year in a CS101 course that used C++. That first course on it's own wasn't too bad, but the subsequent 'introductory' courses for more C++ and Data Structures + Algorithms were just terrible. I couldn't absorb anything useful from them because I was just overwhelmed with the constant bombardment of Segmentation Faults everywhere. Poor teachers + high learning overhead as a result of using a low-level language, just made me want to stray as far away as possible from ever using a 'C-langage' again. If it wasn't for me discovering Python around the same time, I probably would've just given up and pursued music or audio engineering instead.

Fast forward to last year, having now learned a ton more languages, I decided to go back and start reading K&R. I didn't manage to get through a whole lot, but from what I read, I liked it. The problem was that I didn't really feel motivated to keep plowing through it. Looking through the snippets of code in it, more and more I began wondering if some things were just outdated practices, or if they were in fact crazy idioms that I would have to get used to when dealing with C. That doubt (as silly as it might sound) did put me off a bit. The explanations in the text were top notch, but again, the code just didn't compel me to type it in like I knew I should.

Now I started reading LCTHW just a few days ago, and I have to say, it is quite awesome. It's a lot more minimal and sparse than I'm used to for a book, but I have been seriously surprised at how effective that method is. At first I was a bit annoyed that a lot of parts were basically saying 'just google it', cause I look to books to present me with a more coherent explanation of things than I can find scattered around the web or in arcane documentation. But as I went on with it, I noticed that the things he makes you look up on your own are generally specific enough that it makes the task of filtering out all the nonsense much easier than if you were researching it on your own. I quickly got into the groove of the book, because it just builds your confidence that you can be pretty self-sufficient in a new environment, even at the early stages of your learning. Combine that with his 'code first, explain later' format, and that book is surprisingly motivating. In just 2 days, I went through the first 17 chapters (currently stuck on the extra credit for the Database exercise), and I just want to keep on going. I think this is the first time I've ever experienced this level of enjoyment and drive from a programming tutorial. I have no idea why this is, but it's damn impressive. I can't wait to get to the K&R portion at the end.

Thanks Zed!

zedshaw3• 15 years ago

> I noticed that the things he makes you look up on your own are generally specific enough that it makes the task of filtering out all the nonsense much easier than if you were researching it on your own.

That's my trick. I actually go googling and make sure that it's something you can find easily with a little nudge. Part of the goal of my books is to teach basic research skills so you can survive on your own. Glad you got that.

And, you're welcome. I'm still working on it, but feel free to fill out comments with problems you hit.

bretthopper• 15 years ago

This should be titled: Learn C The Hard Way

It's for the C version, not the top level domain.

edit: titled was fixed. Thanks!

babarock• 15 years ago

Wasn't this same book on the front page of HN just a few weeks ago?

It just seems so random to see it appear again today? Was there a special release announcement that I'm not seeing?

farslan• 15 years ago

The page that was on the front page a few weeks ago was just a respond to K&R's C book from the author itself.

Locke16892• 15 years ago

Hmm, I've always viewed K&R as kind of a paragon of C perfection -- I first learned C from K&R when I was 16 or so and have used it as a trusty companion to systems C programming all the way through grad school. Not only do I view it as a good book to learn C, I also view it as one of the best computer science textbooks ever written, partially because it manages to encompass so much of the C and UNIX style along with the programming language itself.

So I guess my question is: why not K&R? Learn Python and Learn Ruby always made sense to me because there's a serious lack of definitive texts on learning those languages, especially if you've never programmed before. However, in my opinion C is not the best first language and there already exists a fairly definitive text on it. So I would love it if someone could let me know what I'm missing.

nikuda• 15 years ago

Your question is addressed by the author at the end of the book:

http://c.learncodethehardway.org/book/learn-c-the-hard-waych...

Locke16892• 15 years ago

Great, thanks!

I'll admit that I don't think I've ever used K&R C code verbatim[1] so I never saw how outdated all the stylistic code was. I would never recommend this primitive style in modern projects. Thanks for your insight Zed!

[1] Really, if you start dealing with the complexities of C at all K&R will no longer do it. First you'll need to read the ANSI C specification to understand what's supposed to be going on, then you'll need to read your compiler's documentation to figure out how they have actually done what the specification says they should do.

pantaloons• 15 years ago

He brings no pedagogical issues to bare, it's simply a facile critique of "style", I don't think that answers the question why not K&R at all.

Some may consider the points well taken, not surprisingly K&R had the foresight to respond in kind, two decades earlier:

Our aim is to show the essential elements of the language in real programs, but without getting bogged down in details, rules, and exceptions.

comex• 15 years ago

Of course the completed portion only includes two examples and they are both stupid. ;)

    while (...)
        if (...) {
            ...
        }
    if (...)
        ...;

"A quick glance makes it seem like this while-loop will loop both if-statements, but it doesn't."

How could you possibly conclude that, considering the indentation?

drucken• 15 years ago

Caveat: only scanned the structure and read the final chapter.

Regarding the final chapter: K&R, like most programming books (especially those for new language) shows pedagogical code, not for productive use. I highly doubt it was ever intended as the equivalent of the modern-day "Code Complete"!

The value of LCTHW, apart from the intro and availability, is its unusual dissecting/analytical approach, which I welcome and am grateful, and for this reason will read it in its entirety.

o2sd5• 15 years ago

OK. NOT TROLLING, but can I ask why anyone would want to learn C, other than to develop device drivers, kernel modules or other arcane software that is yet to be replaced by C++?

I asked this question of a younger programmer the other day, because it seemed to me, that to HIM, learning C was a rite of passage, and that he was less of a man for not knowing it.

I find macho philosophies in software development both amusing and counter-productive.(If you really want to be macho, become a lisp hacker). My amusement may be personal, but the counter-productivity of using C, when better abstractions (i.e. programming languages) already exist, is real. It creates fiefdoms and priesthoods that are counter-evolutionary and hard to maintain, and leads the death of much software.

Personally, I would rather std::string be pored over by many eyeballs and evolved than change strcpy to _strcpy or strlcpy. Unless I am working for NASA on an embedded device for a satellite, I would rather Moore's law or SMP or DSMP give me the speed I need, than give up productivity to squeeze every last CPU cycle. Developer time is a lot more expensive than hardware (except on satellites and space stations).

Apologies if it is your ambition to work for NASA on embedded devices in space stations, I just think you may as well learn C++. You get most of C, plus some really useful and productive abstractions as well.

If you want speed, learn inter-process communication and the principles of symmetric multi processing. With C++, you also get to abstract away the problems of strcpy and strlen, replace Byzantine function references with class methods, and 35 parameter functions with polymorphism. Best of all, most of the programming world will still think you are manly if you know C++, so you get that too.

Peaker• 15 years ago

Not all of us see C++ as an improvement over C.

Sure, C++ has great advantages, but it also great disadvantages.

I use C for many things not because of "macho", but because C is good enough. I can work around the disadvantages using standard techniques. The result is code that is easily FFI'able from any language, quicker to compile, has a smaller footprint, sane error messages, easily debuggable in gdb, etc.

Also, there are some advantages in the abstractions that C encourages you to use. For example, lack of templates pushed C programmers to discover intrusive data structures, and those are better in many ways than templated containers ala STL.

Another example: "virtual" methods may fail to override a base class method if you make a typo - resulting in potentially cryptic bugs. Using a simple macro in C:

  #define MAKE_VTABLE(prefix)  { prefix##foo, prefix##bar }

I can make vtables that are safer than C++, and require no more boilerplate than C++ code. The compiler will guarantee that I implement all of the required vtable methods.

If I want to get speed via multi-core rather than pure uniprocessor speed, why use C++? I can use Haskell and get much easier and safer parallelism with many other advantages.

o2sd5• 15 years ago

Thanks for your reply.

> Not all of us see C++ as an improvement over C.

I know, but you are the first I've encountered to quantify it.

> The result is code that is easily FFI'able from any language

I agree that this is a big advantage for interoperability. While it's possible to build an interface in C++ with 'extern C', it means maintaining two call APIs rather than one. Still I see this as a current limitation of C++ rather than an advantage of C.

> Using a simple macro in C:

Is generally a pain as the macro is expanded at compile time and causes difficulties debugging. Your point about VTABLEs is well taken however and I have encountered subtle bugs with virtual member functions in C++.

> If I want to get speed via multi-core rather than pure uniprocessor speed, why use C++? I can use Haskell and get much easier and safer parallelism with many other advantages.

You would need to enumerate those advantages for me to answer. Why then wouldn't you use Haskell instead of C?

Synaesthesia• 15 years ago

Objective-C is a strict superset of C, so learning C helps a lot for any iOS or Mac programming.

C++ is also heavily based on C, so it helps to learn C++.

I agree C is hardly used anymore, and for good reason, but it's still interesting to learn.

o2sd5• 15 years ago

If I wanted to do iOS/Cocoa programming, I would go straight to Objective-C, bypassing C without stopping, but that's me.

I learned C++ without ever learning C. Although, one could make the argument that in learning C++, I learned about 80% of C anyway. I can debug and fix C code, but I don't enjoy it, and avoid it if possible.

C is interesting, in the same way that Cuneiform is interesting. Personally I just find the Roman alphabet a lot more productive.

wazoox2• 15 years ago

The Linux kernel is in C. Large parts of the Gnome project are in C.

masklinn2• 15 years ago

> I agree C is hardly used anymore

Any time you want to provide libraries, you'll likely use C: all languages have C FFI, and it's not possible to have a C++ FFI. So you'd have to rely on `extern C`, and then you have to build a bunch of stuff over your OO code so it can be used procedurally.

Often not worth it, C is the lowest common denominator of languages, if you want to be accessible to all languages... you'll probably use C.

gillianseed• 15 years ago

> I agree C is hardly used anymore

Ehh what? From the top of my head I can think of these things written in C:

linux bsd windows nt kernel python php perl sqlite gcc glibc gtk+ apache nginx gimp blender mplayer wine x264 ffmpeg libjpeg curl/libcurl zlib rsync

And there's obviously tons more I could think of if I spend some more time, then we have basically the entire embedded industry.

exDM692• 15 years ago

>> OK. NOT TROLLING, but can I ask why anyone would want to learn C, other than to develop device drivers, kernel modules or other arcane software that is yet to be replaced by C++?

Why does a medical doctor have to learn a little bit of Latin? After all, you should be able to find all the books and material you need in your native language or at least English.

C is to computing what Latin is to medicine. There's just so much history and important code written in C, that it's an important skill to master. Or at least know a little about.

These days you can spend your entire career in the comfort of a high level language working on a virtual machine and make a fortune. However, if you don't know C (and the fundamentals of how computers work) you'll be standing on a foundation that you cannot understand like a living in a cargo cult.

If you're passionate about computing and software engineering, you'll have a natural interest in how things work under the hood. Learning C is almost mandatory if you want to see how deep the rabbit hole is. Knowing it will certainly help when exploring the intricacies of processors and operating systems.

Learning C++, on the other hand, I think is optional. I'm pretty seasoned with C++ but these days I prefer plain old C for low-level tasks. In theory, it may be possible to learn C++ without knowing C, but in practice it's not. If you try to write anything with C++, it will be inevitable that you'll have to interface with C code. std::string and std::map are very nice but there's a ton of tasks that require using a C API (maybe through a wrapper layer).

Embedded and other low-level tasks are often written in C because in order to run C++, you need runtime support for exceptions, static & global constructors, etc. Porting the C++ standard library is even more painful. C++ without exceptions has very little advantage over plain C.

o2sd5• 15 years ago

> If you're passionate about computing and software engineering, you'll have a natural interest in how things work under the hood.

When I was 12, I learned 6502 assembly language. The computer I had did not have a C compiler, only BASIC or assembler (you could also enter hex into memory locations, which was hardcore). Learning assembly is actually a LOT easier than people make out. Assembly is basically mnemonics for the underlying machine code, plus named locations. Assembly has everything a language needs for Turing completeness. Assign, Add, Subtract, Compare, Branch. And THAT is how the computer works 'under the hood'. C is one level of abstraction above that, and while it's true that a LOT of software has been historically written in C, before C came along, most software was written in assembler or BASIC (which is older than C, for the historians).

> Learning C is almost mandatory if you want to see how deep the rabbit hole is.

Not really. I know what is going on 'down there', regardless of which language was used to compile the machine code. What is REALLY useful is to have really succinct, powerful, high-level abstractions to build software quickly and with as little code as possible.

> Knowing it will certainly help when exploring the intricacies of processors and operating systems.

If that's what you want to do, then fine. I'm too much of a utilitarian for that kind of exploration. I want to build stuff.

I think if you want to understand what's going on 'down there' in the 'rabbit hole', learn assembly language. There are only seven to ten basic instructions and you can learn them in a couple of days. You can build anything you want in assembly language, if you have an eternity to do it in.

Learn C The Hard Way

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