I'm still a beginner and learning. In tutorials there's usually examples like: using "If...else" to check if the login password is correct, else show "incorrect password" or anything like that.
My question is: do programmers really use such basic control structures in this simple way in final real life projects?
Although both the question an this answer might be considered off-topic, the answer is yes, programmers do use basic control structures, as I can tell from my experience as a professional programmer. Basically, larger systems of software are just more complex than smaller programs, but do not use substantially different language constructs.
That being said, there are various techniques to organize things like structured programming or object-oriented programming, but at the end of the day some basic control structures have to be executed somewhere.
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I'm writing to ask for some guidance on choosing a language and course of action in learning programming. I apologize if this type of question is inappropriate for Cross Validated, please advise me to another forum if that is the case.
I've seen thread after thread with questions from newbies, asking, "What is the best language to start with?" and then it always starts a flame war or someone just answers, "There's no best language, it's best to pick one and start learning it." My question is a little bit more focused than that.
First off, I've been programming my whole life, in very limited capacities. My deepest training was in C++. Whilst in my EECS degree program, I resolved to never be a software developer because I couldn't stand not interacting with people for such long periods of time. Instead I realized I wanted to be a math teacher, and so that is the path I have taken.
But now that I'm well down that path, I've started to realize that perhaps I could develop my own software to help me in the classroom. If I want to demonstrate the Euclidean algorithm, what better way than to have a piece of software that breaks down the process? Students could run that software as part of their studies, and the advanced students might even develop programs for themselves. Or, with an Ipad in hand, why not have an app that lets students take their own attendance? It would certainly streamline some of the needs of classroom management.
There's obviously a lot of great stuff already out there for math, and for education, but I want a way to more directly create things specific to my lectures. If I'm teaching a specific way of calculating a percent, I want to create an app that aligns with my teaching style, not just another calculator app that requires the student to learn twice.
The most I use in class right now is iWork Numbers/Microsoft Excel for my stats class. Students can learn the basic statistical functions, and turn some of their data into graphs.
I have dabbled a bit with R, and used Maple in college. I've started the basic tutorials for OS X/iOS development and have actually made good progress making an OS X app that takes a text string, converts it to numbers, and performs encryption using modular addition and multiplication. I sometimes use Wolfram|Alpha to save myself some time in getting quick solutions to equations or base conversions. I know of MatLab, Mathematica, and recently people have been telling me to check into Python or Ruby. I also know basic HTML, and while it's forgotten now, learned Javascript and PERL in college.
If I keep on the path of Obj-C/Cocoa, I think it will have great benefits. Unfortunately, anything I produced for Mac would only be usable on a Mac, so it wouldn't be universal for all of my students. Perhaps then learning a web language would be better. Second, I'm wondering if the primary use is mathematical, then perhaps my time would be better spent learning Mathematica Programming Language, or R, or something based less on GUI and more on simple coding of algorithms, maybe Python or Ruby?
It seems that Mathematica already has a lot of demos for different math concepts, so why reinvent the wheel is also a question I have. I think overall, it would be good to have more control and design things the way I need. And then, if I do want to make an "Attendance" app or something else, I would already have the programming experience to more easily design something for my iPad or MacBook.
The related question to this is what is a good language to teach to my students? In his TED talk, Conrad Wolfram says one of the best ways to check the understanding of a student is have them write a program. But if Mathematica does the math virtually automatically for them, then I'm not sure that will get the deeper experience of working out logic for themselves, like you do when you're writing C, or a traditional procedural language.
I know that programming takes time to learn, but I also know that at this point, my goal is not to be able to make an app like "Tiny Wings." With the app store ease, some of my work may be an extra revenue stream, but I see myself as more of a hobbyist, and now teacher looking to software development specifically for its ability to help me demonstrate mathematical concepts.
I think I will push ahead with Obj-C/Cocoa for OSX/iOS, but if anyone has some better guidance regarding all of the other available stuff, it would be much appreciated. I don't think I would want to go fully to the web (I like apps), but perhaps someone could suggest a nice way of bridging what I produce in XCode to a universal web version. For example, if you come up with an algorithm in obj-c is it easiest to transition that to ruby and run it online, or is there another approach that works better?
Mathematica is pretty awesome for the first part of your question. I've used the interactive mode (Manipulate[]) for explaining things to my colleges (and myself). It makes really nice dynamic figures and is fairly expressive (although your code can end up looking like line noise). It is very powerful, but it does far less for you than you might think. It's pretty intuitive, which is a good thing for teaching.
You could use Scala if you want an "easy" way to make a domain specific language for teaching. Python seems to confuse people as a first programming language. Objective C seems like a completely random choice to me.
Mathematica then. It's worth the price. But anything that is interpreted and has an interactive shell is probably better than a compiled language. BBC BASIC?
Nothing beats Haskell for general-purpose mathematical programming. The wiki's quite extensive and the IRC channel (#haskell on Freenode) is great for asking questions. If you statically link your binaries on compilation, you should be able to run your programs on just about any system (with a few exceptions, e.g., libgmp).
Haskell code reads (roughly) like mathematical notation once you get the hang of it, so it can really help to tie things together for your students who are motivated to write their own programs. The purely functional style can be beneficial, as well, since it focuses less on I/O and the marshalling of data (perfectly useful in applications, perhaps less so in pure math), and more on the actual creation and refinement of functions and algorithms. You can even compose functions just as you would on paper.
If you want to get really serious, you could also look into Coq or Agda, but those might be a bit much for most classes.
For a Haskell program idea for an educator, check out this link.
A nice list of arguments can also be found at:
Eleven Reasons to use Haskell as a Mathematician and the book The Haskell Road to Logic, Maths and Programming
i am new to asp.net and i was told that i need to know UML thoroughly to build successful software, is this correct? i mean cant i just "code and fix" and "model" in my brain. how important is UML and what is the best way to learn it?
UML is a standard used to convey information about the design of an object oriented software system in a (mostly) graphical format.
It is important as it makes communicating about such a system easier.
UML is a simple way to graphically document a system and its interactions. Its value to you is not necessarily using UML itself, but the value of documenting a system before coding or modifying it.
I see the advantages as
You are forced to think about the whole design before you start building. A drawing is a lot easier to change than a whole lot of code. Mistakes at this stage are easier to rectify.
It helps to understand the system and interactions far better than code alone can. With all the self-documenting code that you can write, a good diagram will nearly always be clearer to and fast to pick up.
The disadvantages are
Takes time to produce, when you would probably rather be coding and experimenting
Can get out of date if effort is not put in to keeping up to date.
i mean cant i just "code and fix" and
"model" in my brain
You can. It's done every day. And a lot of what's going through it at the time, and how you convey your ideas on napkins is already a form of UML without its rigid nomenclature.
But if you're working with colleagues on big systems, there may be occasions were they speak the language.
Metric time is documented here.
I'm looking for any implementations of Metric time to Anglo-Babylonian Time (see article link) either as a library or built-into a programming language.
With all the "joke" programming languages out there, it's possible that someone has done this.
P.S. I realize that it is trivial. This question is for FUN.
The page you mentioned has a UMT clock on it, and the source is in JavaScript. This script seems like a good place to start, it is pretty short and easy to read. Translating it to another language would be cake. I somehow doubt that there are too many libraries, and almost certainly no languages with it built in.
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I would like to learn a functional programming language to see a different programming paradigm.
My background in programming: Java (I have just passed the SCJP exam), some ruby and very limited Rails. I use bash for basic sysadmin tasks. I use Ubuntu 9.04.
As a second goal I would like to use fp to show kids (14-18 years olds) how math and cs interrelated. The guys are very good at programing (they are learning Python and Java at politechnical high school from the first year). However as tests show, they have difficulties with math esp. basic concepts of discrete math. I think we can develop their math skills by using programming (and I possibly that can be the topic of my teacher training thesis). I think a language with very basic vocabulary would serve this project best.
I vote for Haskell, which has the following advantages:
In Haskell, the simple case is actually simple
The complex case is (usually) still comprehensible by ordinary human minds
It has an ordinary syntax that's not too different from other non-functional programming languages (unlike, say, Lisp)
I'm a big fan of Scheme, not least because the best book on it is freely available.
If your primary goal is to work with teens, it makes sense to use the functional-language pedagogy and technology that is proven to work with teens, and that is PLT Scheme (aka DrScheme) with the How To Design Programs book (also free online). These guys have got great results from middle school through 3rd semester university. They have resources for teachers as well.
Many respondents like SICP. It is a wonderful bookâbut not to
learn from. If you already know Scheme, it is a good book to admire, but SICP is less about functional programming and more about how to implement all known interesting computer-science ideas in Scheme.
If your primary goal is to learn a really new programming paradigm, then Scheme lacks some features that are very important to many functional programmers:
Programming with pattern matching
Partial application of curried functions
A polymorphic static type system
Pure functional computation
If you want exciting ideas, try Haskell; Haskell makes it a lot harder for you to program your old thoughts in the new language. Instead, Haskell forces you to think new thoughts. In addition to many other resources, Real World Haskell is free online.
Final note: SO has had many similar questions on learning functional programming.
Scala and Clojure both run the JVM so you might be more familiar with their environments.
I'd try Scala. It's not purely functional, it allows you to use a variety of approaches--but much of your java knowledge should port (It's JVM based) including the JDK libraries, and it's one of the most advanced languages I've ever seen.
If you're interested in learning language features and expanding your knowledge of how languages work, I couldn't imagine a better alternative.
My vote goes to Scala or F#, which are both freely downloadable at the moment.
The advantage here is that they are mixed paradigm languages -- Natively they are functional languages, but you can also use imperative and Object Oriented programming. They also have large standard libraries -- Scala rides on the back of Java and F# has all of .NET, so you can program something interesting fairly quickly.
Scheme and Haskell are both pure functional languages, but unfortunately their standard libraries are relatively small, so it's hard-ish to do relatively common things, like parsing XML or scanning web pages.
Since you're already familiar with Python, why not just use its functional capabilities? For more, see this (draft) HowTo.
My question is what approach is likely to be best for the teens you're working with. If they're willing to learn something new and different, Scheme is an excellent choice as a functional language. It's as basic as they come. If you want to keep to a more familiar syntax, Haskell might be your answer.
If you are doing this for learning, then definitely Scheme with SICP. It's going to be hard and frustrating and will blow your mind if you don't have experience with this stuff, but you will learn a lot.
If you want to use functional programming in practice then F#, Scala and Clojure are worth looking at.
SICP - "Structure and Interpretation of Computer Programs"
Explanation for the same would be nice
Can some one explain about Metalinguistic Abstraction
SICP really drove home the point that it is possible to look at code and data as the same thing.
I understood this before when thinking about universal Turing machines (the input to a UTM is just a representation of a program) or the von Neumann architecture (where a single storage structure holds both code and data), but SICP made the idea much more clear. Scheme (Lisp) helped here, as the syntax for a program is exactly the same as the syntax for lists in general, namely S-expressions.
Once you have the "equivalence" of code and data, suddenly a lot of things become easy. For example, you can write programs that have different evaluation methods (lazy, nondeterministic, etc). Previously, I might have thought that this would require an extension to the programming language; in reality, I can just add it on to the language myself, thus allowing the core language to be minimal. As another example, you can similarly implement an object-oriented framework; again, this is something I might have naively thought would require modifying the language.
Incidentally, one thing I wish SICP had mentioned more: types. Type checking at compilation time is an amazing thing. The SICP implementation of object-oriented programming did not have this benefit.
I didn't read that book yet, I have only looked at the video courses, but it taught me a lot. Functions as first class citizens was mind blowing for me. Executing a "variable" was something very new to me. After watching those videos the way I now see JavaScript and programming in general has greatly changed.
Oh, I think I've lied, the thing that really struck me was that + was a function.
I think the most surprising thing about SICP is to see how few primitives are actually required to make a Turing complete language--almost anything can be built from almost nothing.
Since we are discussing SICP, I'll put in my standard plug for the video lectures at http://groups.csail.mit.edu/mac/classes/6.001/abelson-sussman-lectures/, which are the best Introduction to Computer Science you could hope to get in 20 hours.
The one that I thought was really cool was streams with delayed evaluation. The one about generating primes was something I thought was really neat. Like a "PEZ" dispenser that magically dispenses the next prime in the sequence.
One example of "the data and the code are the same thing" from A. Rex's answer got me in a very deep way.
When I was taught Lisp back in Russia, our teachers told us that the language was about lists: car, cdr, cons. What really amazed me was the fact that you don't need those functions at all - you can write your own, given closures. So, Lisp is not about lists after all! That was a big surprise.
A concept I was completely unfamiliar with was the idea of coroutines, i.e. having two functions doing complementary work and having the program flow control alternate between them.
I was still in high school when I read SICP, and I had focused on the first and second chapters. For me at the time, I liked that you could express all those mathematical ideas in code, and have the computer do most of the dirty work.
When I was tutoring SICP, I got impressed by different aspects. For one, the conundrum that data and code are really the same thing, because code is executable data. The chapter on metalinguistic abstractions is mind-boggling to many and has many take-home messages. The first is that all the rules are arbitrary. This bothers some students, specially those who are physicists at heart. I think the beauty is not in the rules themselves, but in studying the consequence of the rules. A one-line change in code can mean the difference between lexical scoping and dynamic scoping.
Today, though SICP is still fun and insightful to many, I do understand that it's becoming dated. For one, it doesn't teach debugging skills and tools (I include type systems in there), which is essential for working in today's gigantic systems.
I was most surprised of how easy it is to implement languages. That one could write interpreter for Scheme onto a blackboard.
I felt Recursion in different sense after reading some of the chapters of SICP
I am right now on Section "Sequences as Conventional Interfaces" and have found the concept of procedures as first class citizens quite fascinating. Also, the application of recursion is something I have never seen in any language.
Closures.
Coming from a primarily imperative background (Java, C#, etc. -- I only read SICP a year or so ago for the first time, and am re-reading it now), thinking in functional terms was a big revelation for me; it totally changed the way I think about my work today.
I read most part of the book (without exercise). What I have learned is how to abstract the real world at a specific level, and how to implement a language.
Each chapter has ideas surprise me:
The first two chapters show me two ways of abstracting the real world: abstraction with the procedure, and abstraction with data.
Chapter 3 introduces time in the real world. That results in states. We try assignment, which raises problems. Then we try streams.
Chapter 4 is about metalinguistic abstraction, in other words, we implement a new language by constructing an evaluator, which determines the meaning of expressions.
Since the evaluator in Chapter 4 is itself a Lisp program, it inherits the control structure of the underlying Lisp system. So in Chapter 5, we dive into the step-by-step operation of a real computer with the help of an abstract model, register machine.
Thanks.