Edsger Wybe Dijkstra: 1930-2002 409
Order writes "Edsger Wybe Dijkstra, one of the founding fathers of computer science and the author of the famous "Go To Considered Harmful", has died on Aug. 6, 2002 after a long struggle with cancer."
"We're not worthy!"... (Score:3, Interesting)
After reading this article, I think we all need to pause for a minute, and consider the insight of this simple observation.
Add his definition of things human minds are geared to list: static relationships. It's perfectly in line with Dawkins statement that human minds are designed to comprehend things roughly human-sized moving at roughly human-speeds.
I keep forgetting how long people have been programming. Think about how many people using GOTO there were back in 1968. Probably only a few thousand. Crazy.
Final GOTO (Score:2, Funny)
Re:Final GOTO (Score:5, Funny)
Re:Final GOTO (Score:2, Funny)
RIP.
Re:Final GOTO (Score:2)
{
die();
reincarnate();
}
Re:Final GOTO (Score:2)
The problem with that is, as Dr. Dijkstra wrote:
"The unbridled use of the go to statement has an immediate consequence that it becomes terribly hard to find a meaningful set of coordinates in which to describe the process progress."
Looks like we won't be mixing humorous programming references and theology after all...
.
Re:Final Exception() (Score:2, Insightful)
Re:Final Exception() (Score:3, Informative)
Rememberances of Dr. Dijkstra (Score:2, Informative)
The Computer Science profession has lost another giant.
Re:Rememberances of Dr. Dijkstra (Score:2, Funny)
Tulsa University had shuffled around some classrooms to free up a large conference room/lecture hall. Well, for those students who were supposed to attend a class in there that day, the administration had put a notice on the board "Class ???? - Goto 426 " (or something like that). Dr. Dijkstra had come in from the back of the room, was introduced, and started speaking - he never looked at the chalkboard the whole time. Well, when it came time for questions, one student (not me) asked him about the notice on the back of the room. Well, Dr. Dijkstra turned about, cleaned off the board, and said something about structuring the overall conversation, and that comment violated good system design.
Re:Remembrances of Dr. Dijkstra (Score:2)
So there's this huge room, with two walls covered in bookshelves, filled with books, periodicals, publications, a picture of Dijkstra in his graduation robes, awards, etc., all neatly arranged. I get the feeling the Doctor has written half of what's shelved there. (Knuth wrote half of the rest, I reckon.)
Dr. Dijkstra sits me down, and after a quick chat, launches into the first problem. It's a proof, fairly simple. After presenting the problem, he sits down in the chair across from me, and waits, quietly and patiently. On me.
I got so flustered I ended up with a B. One of my great regrets.
EWD Archives (Score:5, Informative)
A pity he's gone.
Respects (Score:4, Interesting)
Re:Respects (Score:4, Funny)
What a thoughtful post! Dictionary.com's pathfinding algorithms were able to find out what you mean by 'respest'. Heh.
Re:Respects (Score:2)
Re:Respects (Score:2, Funny)
More articles (Score:5, Informative)
Some links from my article that slashdot rejected some hours ago: the University of Texas announcement [utexas.edu] has a list of his awards and discoveries. (He taught at UT.) A brief paper [utexas.edu] (in PDF, it's scanned from a handwritten paper for CACM if I recall) shows his brilliant, clear, and concise methods of thought and writing.
If you ever used an application that made use of shortest-path searching -- say, any real-time strategy game -- then you owe this man a debt of gratitude.
Re:More articles (Score:2, Funny)
Not just RTS games... (Score:2)
I believe the Internet core routing protocols use Dijkstra's shortest path algorithm, whereas RTS games probably use the A* algorithm to find approximate shortest paths. So everyone who accesses slashdot remotely uses his algorithm... :) IIRC, Dijkstra also developed semaphores and mutexes, according to our old friend Andy Tannenbaum, which are an absolute requirement for any multitasking, multithreaded OS. Gosh, the man was a legend...
Another great quote (Score:5, Insightful)
"Computer science is as much about computers as astronomy is about telescopes."
depends on whether math is a science (Score:2)
Re:depends on whether math is a science (Score:2)
Re:Another great quote (Score:2)
Under this definition Computer Science as normally experienced is not "science". It is rather a branch of mathematics.
If you mean "computer science" as the study of natural phenomena that are then harnessed to construct computing machinery, then, yes you can have it as a science.
Re:Another great quote (Score:2)
Well I got my degree in CS from one of the top academic CS institutions in europe (the world?) Imperial College [ic.ac.uk] and it's a MEng (i.e. an engineering degree). On the other hand, I remember reading a quote from someone famous (I forget who) saying CS was more like a cross between Maths (logic), Art (creativity & expression) and Biology (evoloution, interactions of complex systems). So I have no idea what it is
Some quotes of Edsger Dijkstra (Score:5, Informative)
Some Quotes of Edsger Dijkstra
"Always design your programs as a member of a whole family of programs, including those that are likely to succeed it"
"Separate Concerns"
"A Programming Language is a tool that has profound influence on our thinking habits"
"The competent programmer is fully aware of the strictly limited size of his own skull; therefore he approaches the programming task in full humility, and among other things he avoids clever tricks like the plague" (from 1972 Turing Award Lecture)
"Progress is possible only if we train ourselves to think about programs without thinking of them as pieces of executable code"
"Program testing can best show the presence of errors but never their absence"
"I mean, if 10 years from now, when you are doing something quick and dirty, you suddenly visualize that I am looking over your shoulders and say to yourself, "Dijkstra would not have liked this", well that would be enough immortality for me"
And then my quote
Re:Some quotes of Edsger Dijkstra (Score:3, Funny)
A very apt last quote for your post. It reminds me a little bit of one of Richard Feynman's friends talking about how he had seen Feynman in a dream, talking very animatedly about something or other, and he thought 'Should I tell him he's dead, or does he already know?'
OK, so it seemed more relevant in my own mind, but he certainly has left a legacy for others to follow.
Re:Some quotes of Edsger Dijkstra (Score:5, Funny)
Was he still talking about programming here?
Re:Some quotes of Edsger Dijkstra (Score:2)
Re:Some quotes of Edsger Dijkstra (Score:4, Informative)
Re:Some quotes of Edsger Dijkstra (Score:2)
EWD certainly knew that, however Simula is a very different object oriented language to the pale imitations that came later.
Simula had a true message passing architecture, C++ does not.
Java and C# have cleaned up the syntax of OOP and have made something of an improvement in this regard but they are both fairly cumbersome when it comes to writing concurrent programs, both lack any meaningful support for parallel constructs.
Basically EWD was complaining about the same thing that I once complained about to Nygaard, Object oriented has ceased to have meaning as a term since it is applied to anything, Nygaard agreed.
My 2 cents (Score:2, Interesting)
I was fortunate to be introduced to Dr. Dijkstra at SIGCSE 2000 in Austin by my advisor. Its unfortunate that our field is so young that its pioneers are just now starting to pass on (compared to other sciences such as Physics, Chemistry, etc.).
Young Science Indeed! (Score:2, Troll)
Yes. Computer science is indeed in its infancy. Dijkstra cleaned up algorithms by eliminating spaghetti code and introducing structured programming. In my opinion, we are still mired deep in the dark ages of computing. If only someone would clean up software engineering by eliminating the algorithm as the basis of software construction.
Do a search on Google for 'synchronous reactive systems' and find out about the next big advance in software engineering.
Project COSA [gte.net]
Re:Young Science Indeed! (Score:2)
No thanks.
So does that mean... (Score:3, Funny)
seriously though, i think dijkstra will be remembered as long as there is the need to prevent race conditions... which in my eyes is quite an accomplishment.
-strangeloop
Sad night on Slashdot. (Score:2)
-Pete
He did so much more... (Score:5, Informative)
Re:He did so much more... (Score:5, Insightful)
The reason that the bulk of the comments here revolve around the whole GOTO thing is because, quite frankly, that is the only one of Diijkstra's contributions that the bulk of Slashdotters are capable of understanding and appreciating.
Most of these posts are quite equivalent to, upon hearing of the passing of Ghandi, saying "Gee, I heard that guy could go a few days without food".
But, to paraphrase the great man himself: in Computer Science most folks miss the science for the telescope. Some things never change.
Rest in peace Professor Diijkstra.
You know you're right but.... (Score:2, Insightful)
There is an old zen saying:
Show a swordsman your sword
Show a poet your poem.
Slashdot is just slashdot.
Re:He did so much more... (Score:2)
It's been a long time since I've even thought about them, but Diijkstra's guarded commands are insidiously powerful. I'm a bit surprised that essentially nothing has been done with them. He once commented that using them, he was using recursion much less. I'm guessing, but I think the power comes from specifying the partial order inherent in the problem rather than inventing a linear order that the program must follow. With a smart-alecky interpreter it might be possible to make a somewhat effective substitute for a nondeterministic finite state automaton.
Sad to see him go (Score:5, Insightful)
In today's computer world, dominated more by marketing folks more than the technicians, I wonder how many people have heard of this man. It is sad that in the last decade of so, CEOs like Bill Gates and Jeff Bezos have gained so much public recognition while people Dijkstra languish in relative anonymity.
A few weeks ago, there was a post in /. about Knuth. I was surprised to see many ask who he was!
Re: True metal survives the acid test of time. (Score:4, Insightful)
and in his time, whom do you think was more famous, Newton or his King/Queen ? Lagrange or whatever Louie ruled then ?
True metal survives the acid test of time. The ornamentations, the hype-sellers, the gates'es and Bezos'es, will be forgotten by everyone (except historians) by the next century.
Dijkstra's shortest-path algorithm and other works will be remembered in centuries to come.
Re: True metal survives the acid test of time. (Score:2)
So true
Commentary on our profession (Score:5, Insightful)
We're getting in on the ground floor. The folks who were there in the VERY BEGINNING of our field are still around to teach us something. We need to remember just how privileged we are to have these fantastic people with us to "pass the torch" so to speak.
Look at how far the medical field has come in its history. Or chemistry. Or physics. And these are just scientific professions.
Think about other things, like teaching or agriculture.
We're the next group to advance CS/E. We've got to adopt these folks as our mentors and learn all we can from them.
Not just _how_ their stuff works, but _why_ they did it. Fundamental practices 30 years ago are as fundamental today as they were then.
"Those who fail to learn from their past tend to repeat it."
RIP, Mr. Dijkstra. And thanks for being such a great mentor.
--NBVB
Re:Learning from the Past (Score:3, Insightful)
It's the "I don't know what it is we're going to do exactly, but I know it'll be done in Java" problem.
The second-biggest crisis in software development today is the bloat problem, IMO. The fact that hardware speeds & memory capacities are following Moore's Law is no reason for us to bloat the code so badly.
Re-writing things that used to function just fine in a new paradigm just for the sake of rewriting it is asinine!
The concept of "Webifying" everything is just silly. Whoever thinks that stateful tasks should be done with a stateless protocol (HTTP) is insane!
Anyway, enough ranting.
And you are completely correct. We need to learn not only the lessons of our mentors, but their mistakes too. Mistakes like C shouldn't ever be repeated...
Oh, did I just say that?
Sorry, I'm letting my personal feelings out again
--NBVB
Re:Learning from the Past (Score:2)
C++ is an inconsistant, bloated, pseudo high-level, partially object-oriented, Frankenstein somewhat C-compatible language.
Re:Learning from the Past (Score:2)
What's wrong with the algorithm?
Predictable runtime, finite outcome.
I like Spaghetti Code (Score:3, Funny)
I read books I picked up from the library for free which showed Basic programs threaded back and forth in sequence, for no apparent reason, and like this sentence, confusing the heck out of me. I saw it as a challenge. I also loved condition gotos'. They were evil.
Gosub? Bah. They ran out of memory too much. Because I hadn't the discipline to Return before I Goto'd out of the subroutine. So I used Goto's to simulate procedures. I also eventually used Goto's in a way that I would eventually learn is like structured programming. Set some variables, goto here, do stuff, goto back, set the same variables something else, goto here, do stuff, maybe goto back. Or it would be the end of the program.
Then I got my first C book. I still haven't got the hang of this language. Before the book even mentions "goto" it gives me a lecture on how awful goto's are and that they can produce spaghetti code. But I *like* spaghetti code. And whats with these labels? Line numbers were so much cooler. But I took the man's advice, I used functions.
But Basic spoiled me. I was never an effective programmer since. It wasn't long after I learned of structured programming that I got my first book on C++ and was introduced to object-oriented programming. Now, for someone using structured techniques for a couple years, the need for objects seemed to make sense. But I was lost in a sea of hierarchial classes and virtual methods.
When I first went on the internet, I started learning all kinds of crazy languages, hoping some of them would be simpler. And there were many. Except for forth and common lisp. Except for ML and Smalltalk. So I am still toying with scheme as I speak, still trying to figure out what exactly the difference between a recursive and iterative process is.
Eventually, I'll figure out how to write spaghetti code in this otherwise clean and elegant language too. Continuations sound promising, from what it sounds like.
I wish the best of Dijkstra--hope he rests in peace. Honestly, I've never heard of him until this post to slashdot.
But maybe it is slightly better for him not to know that some of us never learn.
Re:I like Spaghetti Code (Score:2)
Re:I like Spaghetti Code (Score:2)
Re:I like Spaghetti Code (Score:5, Funny)
Come on, Taco. Post under your own name.
Abandon hope... (Score:2)
Re:Abandon hope... (Score:2)
In a way I know what he means - but he's wrong. I did a lot of Basic, Assembler and Opcode before I got into OOP. Those are 2 completely different ways of thinking, I'll give him (and everbody else) that.
The Problem isn't the students though. Until now (15 years of computing) I haven't met a single softwaredeveloper with significant OOP skills that could actually explain to normal people how OOP works. CS theorist are big at insulting hands-on programmers. But as soon as it comes down to getting the message across and the team going they're often utterly clueless.
I've learned the hard way. It took me years to grasp OOP even though I did programm years before - and I'm still chewing on my design patterns and UML. But when I'm finished, I'll actually be able to teach 'spagetti coders' the way - and not just bullshit about them like the arrogant rest of the pack.
1968 (Score:2)
Re:I like Spaghetti Code (Score:2)
But then a slashdotter told me Microsoft was evil.
Quotes (Score:5, Funny)
re:guards (Score:3, Interesting)
Re:guards (Score:3, Insightful)
Dijkstra's mindset is not for everyone. It's the mindset of a computer scientist who wants to have confidence in his code, confidence that does not come from ego (I am aswome, therefor my code never stinks).
I think the ugly hack has it's place. After all, breaking a window is usualy a bad way to accomplish something, but if the context is you're trapped in a burning house, it's more likely a good move. Bodgeing it out has a similar context, but 99% of the people who don't value clean, well considered code are not in that context. And of the 1% who are, I would bet many of them are in that burning house because someone before them didn't value clean and well considered code.
drop this /. thread and read Dijkstra's work (Score:5, Interesting)
Just looking at his U texas [utexas.edu]publication list is an awesome (pre-1990s meaning) experience. Let your eyes scan it, as they would the Grand Canyon. Then wander around the UTexas site, where many publications are online, and start reading. You'll be a better person for it. And you may experience a thrill of understanding, when you see that his hands hold up so much of today's code, as Shakespeare's hands hold up so much of the language and common experience of the English world.
To get a feel for the span of his life's work, consider his thesis title, "Communications with an automatic computer." The word "automatic" was necessary then, to distinguish it from a person with a calculator. The machine he used in his thesis? It had a 32K memory unit. He divided this into what he called "living" and "dead" memory.
Let's hope that his memory will be of the living variety.
To a man I never shall meet, thank you.
Is it really *objectively* better? (Score:2)
I am frankly not convinced that he found that nested blocks are *objectively* better than goto's. His description is not really rock-solid reasoning in that paper that I can ascertain.
Nested blocks are "better" because they are more consistent from programmer-to-programmer I have tentatively concluded.
More about my GOTO ramblings at:
http://geocities.com/tablizer/goals.htm#goto
There is yet to be a "killer proof". I heard that when that paper came out there was a lot of contraversy. Goto fans rightly claimed that it was just an opinion. Regardless, most programmers now prefer nested blocks for the most part, whether they know why or not.
I can't find any GOTO fans to interview, so their preference reasoning is unfortunately lost to history it seems.
Re:Is it really *objectively* better? (Score:2)
In this whole crazy world, perhaps somebody does.
It is an interesting philosophical issue IMO that serves as a microcosm (practice) for more complex problems, such as paradigm and programming language debates.
If you in particular don't care, so be it. Just don't come whining to me when you find you lack the skills to *articulate* why your favorite language is better than Joe's.
God Bless Dijkstra (Score:5, Insightful)
This man contributed many great ideas to our field. The sad thing is how many programmers are still in ignorance of them, even now. You did great things, Mr. Dijkstra, and will be sorely missed. I just hope we're still allowed to have generic computing devices in ten years' time, so we can continue to refine and develop the revolutionary ideas you left us with.
Dijkstra's shunting yard... (Score:2, Funny)
I'm surprised he was alive in my lifetime... (Score:2)
You want to honor Dijkstra? (Score:2)
Learn what he taught. Avoid GOTO. Learn about structured programming and CSP. Strive for elegance and simplicity in your programs. I can think of no better testament to his work than to show that we really were listening.
zerg (Score:2)
Dijstra's papers from the mid 1970's. (Score:5, Interesting)
I've kept a whole boxful of his papers over the years - just because they are so fascinating to browse.
He invented his own programming language for expressing algorithms - but doesn't seem ever to have written a compiler for it. He refers to algorithms his mother came up with...almost every document has something interesting like that.
The notes are written in the most perfect handwriting you've ever seen.
They could have been printed - they are that precise. Then, one of them out of the blue seems to have been written in someone else's handwriting - it's just as amazingly neat though and when you get to the end of it, it says something like: Apologies for the poor handwriting in this note, but my left hand could use some practice.
These cannot be stored as text files without losing most of their historical interest. Maybe I should spend an evening or two to scan them and put them online. There could be no more fitting tribute to the man.
They're scanned and webbed already (Score:4, Informative)
EWD - Algol, the stack model and recursion (Score:3, Funny)
goto, his development of the stack model was an
evolutionary leap in the development of computers.
Every computer made today embodies his model.
Interrupt handling, recursion, reentrant
programming, multi-programming, multi-processing,
virtual memory all come out of Edsger's model.
I had the great fortune to work on a Burroughs B5500
and later the first B6500 that made it out of
manufacturing. This entire series of computers
was based on Edsger's model and his Algol 60 compiler.
Tony Hoare may have put it best when he quipped
"Algol is an improvement over all its successors".
Certainly Edsger was an improvement over most of
his successors.
Jim Tarvid
A great loss... (Score:4, Insightful)
Moderators: This is one of those posts where I say screw karma. Mod me to redundant hell if you wish, it just doesn't matter.
This is an extremely sad day for computer science. There is hardly a field in CS that Dijkstra's work didn't touch. His work can be seen everywhere we use computers.
Personally, this is an extremely sad day for me as well. Although I never met the man or saw him speak (now one of my greatest regrets), being in college, he's my equivalent of a Joe DiMaggio or a Ted Williams. This man was a hero and an inspiration to me.
Sometimes it really pisses me off that we show such public sorrow for sports figures who pass away like Ted Williams who for the most part didn't do a damn thing to really and truly improve our lives (granted Ted Williams was a marine and fighter pilot but that's not why most people were mourning him). This man greatly and directly contributed to a vast improvement of our quality of life as human beings. His obituary will be a foot note and page Z-42 of the NY Times and Washington Post but when celebrities die, they're front and center on page 1. It makes me sick.
That's my 2 cents and I'm not giving any damn change. >:o
Re:A great loss... (Score:2)
Personal Experience with (Score:2, Interesting)
k u r t AT s p a c e s h i p . c o m
Dijkstra's Law (of programming inertia) (Score:2, Interesting)
If you don't know what your program is supposed to do, you'd better not start writing it.
I'm very sorry to hear he's died, even though I never met the good Doctor. In fact, each time I'm led off into the weeds by some dumbass project manager who misinterprets XP or RAD or ??? into contradicting this law, I quote Dijkstra's Law to anyone nearby. Along with quoting from Yourdon's "Death March", it's my favorite self-help therapy method.
goto alternative: comefrom (Score:3, Funny)
comefrom.
Linux Kernel (Score:5, Interesting)
Those who actually read the linux kernel source codem probably already knew Dijkstra and his god-like powers in the computer-sciences.
But for those who put their nose in there and juts read the comments, there are some references
Fr example: drivers/scsi/NCR5380.c
A few years back.... (Score:2, Interesting)
So, here's to a great computer scientist and a "nice old man". May he rest in peace.
So long, and thanks for all .. (Score:4, Interesting)
This software engineering class was very pragmatic, emphasizing methodical design, implentation, and testing. As I recall, Dr. Dijkstra gave his lecture near the end of our semester, by which time we had been heavily involved in something resembling a team development evironment for a few months.. There was a very corporate feeling to our regimen of meetings and reports.
So one day we all go to the faculty lounge to hear the esteemed professor speak. He comes in the door of the lounge appearing to me most unlike the kind of man who could write so forcefully about programming, dressed in shorts and a tee-shirt with a distinctly old-grandfather look on his face.
In his very soft-spoken manner, he told us that he beleived that the main problem with programmers was a lack of rigor. People were so concerned with coding and testing that they never learned how to write something correctly the first time. He asked us to prove the correctness of the code for a binary search and spent the next half-hour proceeding glumly as we slowly worked through the process with him.
I got the impression we were a vaguely dissapointing group of students who he could tell were not convinced of the validity of his approach. It wasn't even a bitter dissapointment, though. I felt as though he was someone who had totally convinced himself that he knew how to make the world a better place, but that noone was listening.
He answered our questions about "gotos considered harmful" (it was his editor's idea to give it the cute title) with what I considered obvious patience. He talked about how he really only was able to keep up on the research that people referred to him these days. And then the lecture was over.
Our professor and Dr. Dijkstra were good friends, and I hung around after class talking with them about computer science and Dijksta's past. I ended up in his office after a while and we chatted about the current state of the industry as he saw it, why he really liked Texas, and so on. He was so intelligent in his conversation--asked so many probling questions--that by the time I was done I felt both touched and exhausted. He put on his cowboy hat and walked out of the office with me and headed off to his next appointment.
That was the last time I saw Esdgar Dijkstra--the only real time I ever talked to him. But I feel that the world has lost a quiet crusader, and I feel a tug in my heart thinking about this old dean of computer science with his cowboy hat.
Even more Dijkstra quotes (Score:3, Informative)
APL is a mistake, carried through to perfection. It is the language of the future for the programming techniques of the past: it creates a new generation of coding bums.
The use of COBOL cripples the mind; its teaching should, therefore, be regarded as a criminal offence.
When FORTRAN has been called an infantile disorder, PL/I, with its growth characteristics of a dangerous tumor, could turn out to be a fatal disease.
COBOL is for morons.
With respect to COBOL you can really do only one of two things: fight the disease or pretend that it does not exist.
The question of whether computers can think is like the question of whether submarines can swim.
Dijkstra (Score:2, Insightful)
Re:Contents of article (Score:2)
I can certainly understand pleading with people to make more sensible code, but I didn't strike me as being that urgent. I don't think I have a full picture of what's going on here. Could somebody enlighten me? I'm really curious.
Re:Contents of article (Score:2)
I've never seen anything that could be accomplished with a goto that couldn't be accomplished by simply calling functions.
Then again, now that I think of it, if gotos are bad, recursion could be considered bad for the same reason - because it can be difficult to tell sometimes where code is being executed. Try following the code in a recursive descent parser and you'll see what I mean.
Re:Contents of article (Score:2)
The classic example is breaking out of deeply nested looping constructs. Note: This does not apply to languages that have exceptions.
Re:Contents of article (Score:2)
Re:Contents of article (Score:2)
And watch your code run like molasses.
Re:Contents of article (Score:3)
Anyone have good profiling tools available for the really good compilers?
Re:Contents of article (Score:2)
Re:Contents of article (Score:3, Interesting)
When I learned to program in the early '70s, our lecturer told us that if we used even *one* 'goto' in our work, we'd score zero for the entire assignment.
I've been programming for ~30 years now and never felt the slightest need to use one in a high level language since that day.
I strongly disagree about recursion though. Used properly, it's *very* readable:
void binaryTree::walk_binary_tree ( void )
{
if ( isALeafNode () )
else
{
leftBranch -> walk_binary_tree ()
rightBranch -> walk_binary_tree ()
}
}
Try writing that more cleanly without recursion!
(NOTE: You may be able to make it faster or more memory efficient without recursion though).
The art of reading and writing recursive programs is to try to forget that they are recursive.
I think to myself:
"In order to walk this tree, I walk the two child branches
- hmmm - I have a function to walk trees - I'll just use it
and assume it'll do what it's told."
The fact that the routine you are calling is also the routine you are currently writing just doesn't matter in most cases.
Re:Contents of article (Score:2)
870 if j go to 800,900,400
Any other questions?
Re:Let's See... (Score:2)
Re:Let's See... (Score:2)
'Wybe' is pronounced as 'Wee-buh' where the 'wee' part is a short sound, not a long weeeeeee
Re:Let's See... (Score:2, Informative)
Normal Dutch:
D'ii'kstra: the ij is pronounced a bit strange, it is hard to explain......
Fries:(northern language/accent)
D'ee'kstroa : the ee is pronounced as in english the seperate e but longer.
Re:Ad placement (Score:2)
switch (value)
{
case 0:
DoSomething();
case 1:
DoSomethingElse();
break;
}
you need to do:
switch (value)
{
case 0:
DoSomething();
goto case 1;
case 1:
DoSomethingElse();
break;
}
the reasoning being that it's better (more readable) to have explicitly defined follow throughs.
Re:Ad placement (Score:2)
I have always looked at the default fall-through behavior of the case in C as a design error - a complete disaster waiting to happen.
Why is it so?
Re:Ad placement (Score:2)
Why is it so?
Because Original C is almost completely a block-structured language. With very rare exceptions (that tend to involve comma-delemited lists of statements), all control structures control a single statement -- the beauty of C, however, is that a block is acceptable in any case a single statement is allowed.
As this relates to the switch/case statement, it becomes a question of what exactly each component can control. The switch statement has to control a list of something, obviously, because it has to contain the cases. What the cases control is a more interesting question.
If the case controlled a statement/block, such as what happens in Pascal, then we end up with code that would look something like this:
switch foo {
....
....
case bar {
}
case baz {
}
}
With structure like that, there is no mechanism for fall through, even explicitly -- using a goto would involve gotos between a block and its sibling (instead of its ancestor), which creates spaghetti-code problems with gotos all over again. The only way that the language could implement fall-through would be through a new explicit statement to do so, and taking that route too many times leads to PL/I or APL.
Kernighan and Ritchie, the designers of C, were expressly designing the language for systems programming -- operating systems and compilers. These people want (and even need) a language that is both high-performance and flexible. To them, a "weak switch," one that allows fall-through, was potentially useful and came at neither a performance nor complexity (of the language) price.
Therefore, the optimal decision was to implement switch controlling a block of statements, with the innovative implementation of cases as labels within those statements. Programmers who used C were supposed to understand what this meant for fall-through, and although I'm sure they made the mistake of leaving out a break occasionally (just as often as Us Normal People leave out semicolons or the like), the error it caused wouldn't be impossible to find or fix.
Re:Ad placement (Score:2)
Re:Damn you Order (Score:2)
So you're running this without any indication that the files you're grepping are really source code (are you running it on a clean
Re:Damn you Order (Score:2, Funny)
(drivers/scsi/NCR5380.c, lines 1466-1468)
Re:Damn you Order (Score:2)
Re:he taught an honors undergrad course at UT (Score:3, Interesting)
He was the person who first made me realize--at a visceral level--that clear thought is as important in a program as clear prose is in writing a novel.
After the final exam (conducted verbally, one-on-one, at his home), he asked me what one thing I would most take away from his class. He seemed to consider my answer to this question more important than my performance on the test itself. I told him what the above about literature and programming. He nodded, thought for a bit, and said 'Very good. Can I offer you some tea before you go?'.
I got an A, so I guess he liked my answer.
Re:Let's hope he's Hindu (Score:2)
Re:Dijkstra (Score:2)
It is practically impossible to teach good programming style to students that have had prior exposure to BASIC; as potential programmers they are mentally mutilated beyond hope of regeneration.
I've always had great respect for the man, but after reading that quote it has increased.
Also to note: More than half the college books I've had to read have some reference to Dijkstra in them. He is one of the greatest contributers to computer science, not only in the theoretical level, but on the practical design level as well.