Correct Approach for mastering SAP R3 and ABAP - abap

I have been working on SAP technology for the last 2.5 years.
As there were so many technical concepts, I couldn't get a single source where I can learn about everything related to it. I didn't get the confidence of mastering all the technical concepts.
Please help me out if you have faced such an experience and how you overcame it.
Suggest some books or a methodology you followed which may be helpful.
Note: I have already worked in Java/J2EE. I am confident enough in mastering the concepts.

Obviously the (or rather a) correct approach would be one that works for you, the conclusion being that you don't know whether the approach was correct until you've tried it. :-)
Enough philosophy - my suggestions would be:
Learn how to read the SAP Online documentation. That's a bit different from reading other documentation - the SAP docs are littered with information about legacy techniques that you don't really need. Learn to identify and skip these parts - you can always come back later.
Develop a knowledge of the data dictionary. It's really at the heart of all things, and if you can't navigate there and read the structures, you're lost. Start reading the chapter in the online docs at http://help.sap.com/saphelp_webas620/helpdata/en/cf/21ea0b446011d189700000e8322d00/frameset.htm.
Read http://help.sap.com/saphelp_webas620/helpdata/EN/fc/eb3138358411d1829f0000e829fbfe/frameset.htm. I know that's a lot of stuff, but it's available for free, and almost everything is in there. Again, do a "fast indexing run" first to get a feeling of what's inside there, then dig into the basic concepts. ABAP at its lowest level isn't fundamentally different from other imperative / procedural languages.
Follow the example programs (transaction code ABAPDOCU). Learn how to use the debugger (vital!) and understand what's going on in the demo programs.
Once you've got a mental model of the basic language, take a look at ABAP Objects. If you already know Java, there should be no problem with the basic concepts, but there are a few specialties.
Feel free to ask if you run into something you don't understand.
There is no single source of information that will provide you with everything you have to know, especially since some of the knowledge is very specific to the context (FI, MM, IS-H, ...).

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Various questions regarding pure OO (Getting set up WITHOUT an ide; Tutorials; The associated books) [closed]

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I've been wanting to get into a pure-OO language for a while now, but I'm put off by the fact that they all seem to demand an IDE and I can't find any good tutorials that aren't in video format.
I'm happy to use an IDE later, but I don't want to learn the language through one. What I'm looking for is a simple console interpreter or command-line compiler such as gcc, ghc, ghci and the python IDLE (yes, it's an IDE, but it's so minimalist that it may as well just be a commandline interpretter). I find that I learn a language faster, better and more comprehensively when I'm not trying to grapple with an IDE at the same time. So please, don't tell me that squeak is the only way to do it :P
I'm also looking for tutorials that are presented textually rather than visually. Again, I learn faster when I can stare at a page and read someone's sentance over and over tossing and turning it in my mind rather than having to pause a video, take it back 10 seconds, press play, do it again, and again, and again.
I'm interested in various languages with various degrees of OO-purity, and I plan to learn them all at some point. Any of the smalltalk dialects interest me, Self (an extreme prototype-oriented version of smalltalk (Very interesting, the more radical the better imo)), strongtalk, vanilla smalltalk (or some implementation which is as vanilla as you can get).
I'm interested in Eiffel as well, the code snippets I've seen make it seem very elegant and I've read that it actually was very innovative (introduced code-contracts and other such things). However I would give preference to a language from the smalltalk camp over one from the Eiffel side because Eiffel at face value seems to be a hybrid between OO and imperative programming. Similarly I'd rather avoid Scala (Hybrid OO and functional) and other hybrid languages. So no C#, Java, C++, D, python etc etc etc. I'm not dismissing these languages because I believe they are bad, it's just that I'm setting out to learn pure-OO and those languages are hybrid OO: Not really what I'm looking for.
Also, would anyone be able to recommend the official books? For smalltalk there's the "Blue book" AKA "Smalltalk-80: The Language and its Implementation". And for Eiffel there's "Eiffel: The Language". I ask because in my experience you can pick up so much by reading books written by the author of the language (see K&R the C programming language), and by reading books in general.
So yes, my questions: What pure-OO language would be good to start off with? How would I go about learning it without having to use an IDE? And is there an associated book written by the language author(s)?
It is not helpful to learn Smalltalk as just another language. You would be missing the point entirely.
Smalltalk's graphical environment is not just an IDE. The core of the system is simply objects. The interface provides various ways to create objects and interact with them. The language is just a convenient way to create messages to the objects. It is secondary to the objects themselves.
In other OO languages, you write your program, then you run it, which creates objects in memory. Not so in Smalltalk. You create objects in memory (e.g. class objects) and then send messages to e.g. add methods. But a class object is only created once, not every time you "run your program".
There is no such thing as "your program", in fact. There is no "main". It's just a world of objects, some longer-lived, some temporary. In fact, in the system there are objects that were created 30 years ago. Literally. The objects are just frozen to disk as a memory dump (a file which we call "image") and unfrozen later (possibly on a different machine).
That image, the world of objects, is the primary artifact in Smalltalk. There is a sources file, yes, but that's just a database of text snippets to not take up so much RAM. You cannot edit this file by hand (objects in the image use absolute file offsets into the sources file). You cannot re-create the system from the sources file - the system was bootstrapped a long time ago and from then on only modified.
It's true that superficially the Smalltalk GUI looks just like another IDE. No coincidence - Eclipse was originally written by Smalltalkers in Smalltalk. But there is the crucial difference that in regular IDEs you just manipulate text files. A text editor is a valid alternative for that. In Smalltalk, the GUI manipulates objects in memory. A text editor can not do that.
And as for what Smalltalk to use, I would recommend Squeak. Very friendly community, very nice environment, and subscribing to the original Smalltalk vision of creating a great personal computing environment for everyone.
As someone who has went through process of learning Smalltalk (at least to a decent degree), I can say that you are taking harder and riskier path, in a sense that some things may take much longer to clear up, or never actually do.
But, if you insist, you can download GNU Smalltalk, for which no GUI is a norm. It also contains all sources of the system written in Smalltalk in a chunk format and you can open your text editor on them and enjoy while slowly reading through the guts of the system.
You could also startup any other Smalltalk, like Pharo, and just stick with a workspace window - this is your equivalent of command line interpreter.
Pharo also includes ProfStef quick interactive tutorial on Smalltalk, which combines text instructions and evaluating Smalltalk expressions.
As for reading, there is Pharo By Example - free book that you can browse, download or buy hardcopy.
There is also a collection of free books in which I would recommend "Smalltalk-80: The Language and its Implementation" By Adele Goldberg and David Robson, if you are interested in the innards and detail of the language.
Late David N. Smith Smalltalk FAQ is also exelent resource.
So, there you go. And take advice, and give in to the Smalltalk IDE as soon as possible, since it makes understanding of Smalltalk much, much, faster.
Richard Gabriel gave a talk recently about a paradigm shift that occurred in the programming language community in the early 90s. He claims that most experts today are incapable of understanding many of the papers from the 80s. He has evidence to back this up. This was the first time he gave the talk, and he expects to give it many times, so I imagine that many parts of the talk will change. At first, he described this paradigm shift as engineering -> science, but then he described it as system -> language. I think that describing it as a shift from systems thinking to language thinking is a better description.
Richard Gabriel is a Lisp guy. (I'm a Smalltalk guy). Lisp is like Smalltalk in that there isn't a clear boundary between the language and the library that it uses. Arithmetic and control flow are in the libraries, not the language. (Well, Lisp has some in the language and some in the libraries, while Smalltalk has it all in the libraries, except that the compiler cheats and hard codes some of them, so there isn't really much difference in the end.) In Lisp, a program is an S-expression, and editing programs is editing S-expressions. In Smalltalk, a program is a collection of objects, and editing programs is editing objects. When you are programming, you are building a system, and you program with the system.
System thinking is different from language thinking. Language thinkers want a precise description of a language. They want a book that describes the whole thing, or (if they are academics) they want a formal semantics for the language. But system thinkers know that as soon as they start to use the system, it will change. They want to understand how the system works, but are prepared to look at the system itself to figure out the details.
These are two ways of thinking, and there are advantages and disadvantages of each. Smalltalk is a wonderful example of systems thinking. I think all software developers should know at least one system that exemplifies systems thinking. Lisp is good. Forth is another old example. Naturally, I think that Smalltalk is great and am happy to help people learn it but I think the importance of learning systems thinking is more important than the particular system you learn.
Unfortunately, learning a system is harder than learning a language. You have to do more than just learn the syntax, you have to learn the libraries, the patterns of naming and of coding, and usually the tools. (Which, if this is a system, are extensible.) That is one of the advantages of language thinking. But systems thinking has long-term advantages, because once you taylor the system to your needs then you can become very productive.
To lean smalltalk syntax, you need to read ONE page of text (see Syntax section on wiki http://en.wikipedia.org/wiki/Smalltalk).
Now, to learn a smalltalk libraries and how to use them, you need to use browser not the text editor, otherwise your will just waste a lot of time.
I think that it is like factor of 10 difference in time, between trying to understand some code by reading in textual format and navigating it using browser and! debugger.
In smalltalk system a living objects could tell a lot about themselves and help you learn how to use them much faster than if you look at it as a static chunks of text, because you won't grasp the idea at all.
I've been playing with Squeak Smalltalk (and its close cousins, Pharo and Cuis) for a while now. There's no better way to learn Smalltalk than by using the system already provided.
I've devised a series of short youtube tutorials ranging in length from 50 seconds to 15 minutes that show how to take advantage of Squeak's ultra-cool features within a few minutes of first starting the system.
In fact, the very first line of code demos the OOP-ness of Squeak. Squeak from the very start
Python is a pure OOP . Actually this is an easy mistake that newcomers make when they come to python.
Python like smalltalk follows the mantra "Everything is an object". So everything inside python is an object, including built-in types. The difference is that python unlike smalltalk and Java does not force OOP as it allows procedural programming. And this is the trap, it easy to assume that makes python less OOP , but being a snake, is so devlish that does not tell you that even functions are objects ;)
http://www.linuxtopia.org/online_books/programming_books/python_programming/python_ch10s04.html
Going back to smalltalk its IDE is the huge deal here, contrary what other smalltalker may believe. If you like me are heavily disappointed with how non flexible IDEs are you are going to love Squeak's IDE. The IDE goes a great deal making easy to navigate through all the libraries and making you understand what , where and why , something happens. I cant see the benefit of using a text editor. But you can, with file ins and file outs. But doing so you cripple smalltalk into becoming as efficient as other programming languages ;)
I am only studying squeak and pharo for a week now but even for me as a beginner the benefits of the IDE is obvious from the first minute.
The fact that code is fragmented into easy to digest methods, those methods grouped into protocols , protocols grouped to our familiar Classes and Classes grouped to packages. Hence the code is so well organized that I never feel lost, everything belongs somewhere, everything is just a click away, everything is inspectable, browseable , you just select right click and sends you there. And it shows you exactly the code you need rarely more than 10 lines long. This is the IDE. Why would you prefer a text editor that will expose to information that you don't need , don't care and is likely to confuse you ?
Then everything is inside a single image , not a collection of files, your code, your libraries, system libraries , even the language itself. Everything is at your grasp, waiting for you, begging you to test, modify it, use it and abuse it. You are part of the language and the language is part of your, if something does not fit your thinking, change it. This is the IDE. Why you want to go back to the disconnected way of files and folders ?
Then you are start being afraid with all this power, all this flexibility its not unlikely that you will do something that could completely destroy the language and the libraries. Its possible , mistakes can and will happen. Again the IDE jumps in offering you a hand of help, every change is stored in a local cvs system, every change is categorized, stored and monitored any time. No lousy undos and any kind of other nonsense . What you get is old , mature well tested version control. You can change back exactly what you want any time, nothing is lost, no mistake is irreversible.
And if you don't trust you hard driver , the vcs extends online to squeaksource . And does it let you at the mercy of command line ? Hell no . You are offered the simple yet efficient Monticello browser , which will make sure you install and unistall with no conflicts .
And of course you don't want your software to have bugs , do you ? Unit Testing tool is offered to make sure your code is reliable , stable and does exactly what you want how you want it. Again a beautiful yet brilliant GUI is utilized to make complicate tasks a button away.
And because none is perfect , there will be time you will come against the dreadful error. Are you left alone ? You guessed right , a tool again is offered. The debugger. You don't need to call it, you don't need to setup it , you don't even need to figure out how it works. Like all other tools, is simple in design yet sophisticated. Not only it will spot the error , not only will tell you what you did wrong , not only will navigate through back to most basic language elements that trigger the error offering a unique perspective on how exactly the language behave like nothing I have seen before, it also allows you to do live coding. Live coding is the ability to code a program while its code runs. Isn't that impressive and infinitely useful ?
Finally , maybe you are one of those people impossible to please, maybe you still find flaws , omissions and thinks you simple don't like. The IDE is written in smalltalk , smalltalk is written in smalltalk , and the IDE can edit itself and the language, there is nothing you can't change besides some very basic functionality of the language and the VM that is compiled C. And you will guess right if you think you can use all the above tools to do exactly that.
And the tools don't stop here , smalltalk might be not that popular as other languages but it has been here for a very long time and it has some very enthusiastic programmers that love to contribute. And frankly with such an amazing IDE and such a well designed language , while with other languages contributing to them might seem a challenge, in case of smalltalk the challenge is to resist the temptation not to contribute as the IDE makes it so easy.
By the time others still code you will finish your code and actually understand what have you done and why. Thats not a small thing at all . I wish Python had such a good IDE or any other language. But the only thing that comes abit close, from my experience , is Delphi. And even in the case of Delphi I still prefer squeak and pharo.
What I find annoying about other IDEs is that they are not IDES at all, they are nothing more than glorified editors, locked, non flexible , non editable (Unless you are willing to use another programming language and navigate through tons of source code) . Squeak , Pharo and all other smalltalk dialects offer a real elegant IDE offering you really useful tools. Other IDEs better take a deep a look at smalltalk and really understand what it means to be an IDE.
Saying all those good things, smalltalk is far from perfect. And I think its biggest weakness and flaw is lack of some enjoyable and useful documentation that can help beginners jump in head first. Squeak By Example as well Pharo By Example has been a big disappointment for me. They both are still two extremely important books that provide a extremely valuable insight in both platforms , but the quality of documentation is from mediocre to bad at times. The main reason is both books follow a non noob friendly approach. First they send you deep diving in the IDE , introducing you from chapter 1 , to debugger and even unit testing !!! For me this a big mistake, and even though I am far from new to programming had to struggle to follow up what was explained. Then the book itself , lets a lot of unanswered questions. For example the explanation of instance vs class variables is not enough, I would prefer several example that not only show the how but also the why . Several areas of the book are also full of gaps or just hard to follow.
My life got a lot easier when I found this link http://stephane.ducasse.free.fr/FreeBooks.html and from there I downloaded "Smalltalk by Example" which unlike the other book not only it does what it says in the title but makes no assumption on who you are and what you know. I can only highly recommend it. I read that the other books there that are offered freely are very good as well, I will certainly download and read all of them eventually.
Alot of help has been also #squeak at irc.freenode.net, people there has been answering my questions and helping me understand.
Squeak wiki, is ok but not enough, its also not very well organised, and I dont like that comments and discussions appear inside the wiki documentation. So documentation generally can be abit of a struggle for the begginer and certainly Smalltalk IS NOT AN EASY programming language to learn. I hear many smalltalkers say otherwise and I could not disagree more, when I compare smalltalk with python is like night and day. BUT ! Once understand smalltalk , it become much easier to program in it then any other programming language I have learned so far, and I have learned most of them. So in the end I think Smalltalk is a clear win , I also love the FFI library that lets you call any C library with ease, which unleashes serious power for smalltalk.
I dont think you need to learn the language first and then the IDE, its actually a very bad idea for the simple fact that the IDE helps you understand the language and its libraries and any type of code in it. Language and IDE is like brother and sister, yin and yang.
Well, if you decide to learn Eiffel a good book would be "Object-Oriented Software Construction" by Betrand Meyer (he created the Eiffel programming language).
The book provides great insight into object-oriented design using Eiffel. In my humble opinion is one of the best OO books around.

SQL Data Mining Concepts VS. Programming Concepts

I am a beginner but know the basics and am peering into more advanced data mining and stored procedure routines. I have learned small concepts that mimic C# Design Patterns such as looping structures but have not seen much (on the web) about SQL Design Patterns.
I ask because I ran across this book http://www.amazon.com/SQL-Design-Patterns-Programming-Focus/dp/0977671542 but have also always been told that you will find better information on sites like Stack than in a book.
I've been told that for programming professionals Design Patterns are a must. Is this also the case for SQL programmers?
*(Wasn't sure if this belonged on Meta or not. It's not a question about the site but is a general discussion question)
Design patterns for SQL are very useful as well. Is it any good to gather data if you do not store it properly and retrieve it back to make useful decisions?
I have found Joe Celco's books very useful on database design patterns. http://www.amazon.com/Joe-Celko/e/B000ARBFVQ
Of course you should read books. In the first place they tend to be written by people recognized for their expertise (not just anyone who happens to log into the site) so the information is likelier to start out as more accurate. Then they have editors who help make the presentation of the information better. Finally a good book should discuss in more depth than an SO post can do and thus you will get information at a deeper level than just the code to fix your current problem. This means your understanding will grow and you will know why you would do X vice Y and be able to expand that understanding to new problems.
DBAs who don't read books probably don't understand the internals of how the database works very well and are likely to be less effective than those who do read in depth about their profession.
A book I recommend is:
http://www.amazon.com/SQL-Antipatterns-Programming-Pragmatic-Programmers/dp/1934356557/ref=pd_sim_b_1
Also books on performance tuning are critical to read if you want to use good patterns in your SQL. A huge number of performance problems are caused by badly designed SQL. YOu should know what works well and what doesn't. Those tend to be databse backend specific, so look for ones realting to the type of databases you support.

How to learn ”the way of ABAP"? [closed]

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I never worked with SAP solutions. I have a reasonable understanding of business, but no accounting background. How to learn ABAP on examples that will simultaneously enlighten me with the "way of SAP"?
It doesn't have to be a deep knowledge, just something to start for somebody who was in the world of Python and C# but needs understand how SAP world works.
(this is not a duplicate of "Learning SAP-ABAP")
Learning ABAP is not particularly difficult if you know other programming languages.
Let's first distinguish between ABAP and ABAP OO. ABAP is the old, procedural language and ABAP OO is its extension with classes.
ABAP has the usual control structures, like if-then-else or loops. Its syntax takes a bit of getting used to (I found especially annoying the part about putting or not putting spaces before parentheses), but is definitely doable.
There are some structures you don't find in C++ and C#, for example the grouping of functions in function groups, which have their own local variables, so if you call something that is in a different function group, things can get messy.
But generally, if you understand scope and namespaces, it shouldn't be a problem.
I found ABAP OO pretty straightforward compared to ABAP, because it basically only added the classes / packages that I knew from C++ / C# before.
How to learn them, I would propose the following for someone who is new to ABAP and wants a DEEP knowledge of it (see later the more functional aspects):
-buy yourself a proper ABAP book, e.g. something from SAP Press
-don't read it just yet
-start with a web course or a simple book, along the lines of "learn ABAP in 24 hours"
-start coding
-as you are coding, you will inevitably ask yourself: "how does this and that work? is the PERFORM using pass-by-reference or pass-by-value for passing the arguments?" Look those questions up in your proper ABAP book
-probably after a few months, you will be familiar enough with the language that you can read through the book without falling asleep
Just a caveat: It IS a useful skill to know ABAP programming, but even if you don't consider the other technologies SAP consists of (like workflow or PDF Forms, that don't have anything to do with ABAP), there are still a lot of frameworks that differ in their logic. So just like even though you know C++, knowing the Win32 framework does not mean you can start banging out code that runs under UNIX, knowing ABAP does not mean that you can work productively in a specific module right away. Unfortunately, SAP modules tend to use different frameworks, some of them more reused than others.
If you do not want a deep knowledge of ABAP, but want to understand the SAP modules functionally, you should consider using the products themselves in addition to programming and learning about the functional aspects.
I'm afraid there is really no quick way to learn how the "SAP World" functions; you need to have a bit of technical, functional and also architectural knowledge for that and since the modules are so vastly different from all those aspects, it takes a lot of time until you can have a vast overview of everything. But even with technical and some functional knowledge you would be well on your way; as they say, "in SAP, nobody expects you to know everything".
There are at least two different sets of issues you should be looking for:
Knowledge of ABAP as a programming language
Knowledge of the "Business Domain" that your writing your software for and its implementation in SAP - tables, forms, programs, reports etc, (and each of the modules such as FI HR etc. is more than a normal person can usually be proficient in)
(1) gives you general knowledge on how to write a program, read and update the database, and maybe write a GUI. But the programs that you write will almost always be in the context of (2), so you will need to know that as well.
If you want to get started, it is best to have some general knowledge of the ABAP language, the business domain can't really be learned from a book. Actual project work is much more helpful.
Start by downloading one of the netweaver trial systems from sdn.sap.com (choose one of the ABAP trial systems).
For reference you have the ABAP manuals online here (the reference documents also have a lot of small example programs). For more example code you can enter transaction SE38 (report editor) and search for programs starting with BC or starting with DEMO (put BC* in the name box and press F4).
since you asked me to respond to this question as well. I was hired as a sap-java-developer because there are very very few on the market, even though I didn't know anything about sap java before I entered. I got advice from my co-workers and learned as fast as possible to become productive. It wasnt such a big deal in the end.
I'm one year into the business now but I'm still in a newbie-state. The sap technology environment is huge. SDN (Sap Developer Network) is my best friend whenever I'm stuck.
It definitely helps when you end up in a company with sap-knowledge because you dont have to build up all systems from scratch and you have the licenses for the various sap products at hand. Most trial versions from sap just wont do the trick on the long run.

How to learn C and Objective-C [closed]

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I am learning programming. I plan on learning C and Objective-C this summer. I bought the C for Dummies book but it is a complete waste of time. It's way too many pages! Are there any good books I should read? Or should I just learn C from websites? What would be the fastest way because I really want to learn it fast and start learning Objective-C too.
Thank you
Also, how long does it take to learn C? Until I move to Objective-C 2.0
There's no need to rush. Learn at your own pace and find your optimal way of learning.
If reading is your thing, then try to read some books and take it slowly.
If you find a concept you grasp, practice. If you find a concept that you don't quite get, experiment. Once you think you understand the concept, try re-reading the material to see if you understand it the second time.
I found out that I wasn't really good at learning though books -- I generally had to get the first kick-start with a structured lessons in a classroom. A semester course at a community college on Java was able to nudge in the direction of being able to begin effectively learning on my own. See if there are any programming courses offered in your school.
(Although at your age it may be a little bit difficult to find -- I didn't get any formal classes until community college -- my high school did not offer any programming courses.)
One of the things to be careful of is learning it the wrong way.
Rushing through material, or reading poorly written, inaccurate learning material can lead to a situation where you'll need to "un-learn" the concepts and re-learn it the right way.
In that respect, the K&R book (The C Programming Language by Kernighan and Ritchie) would be the "right way" of learning, but it's not a very approachable book. That isn't to say that it is the definitive book on C -- but even after programming in C for a couple years, I still try to take read it a bite-size at a time.
But then again, I can't really think of other "great" sources for learning C. My recommendation would be to take a look at K&R and work on a few pages at a time. Don't think about reading it like a regular book -- read one section, try it out. Do it little-by-little. Once again, don't rush. Work at your own speed.
And be sure to write code. Without seeing it working, it's going to be difficult to learn programming. And don't have huge expectations at first, as most of learning C at the beginning will involve programs that deal with only text.
Once you get a handle of things, try to write clean code that is readable by others -- that should be a motivation to write clean and clear code, and it will force you to think harder about what you're doing.
It's going to be a long adventure, so take it a step at a time. Good luck!
For learning C, I highly recommend Learn C on the Mac, by Dave Mark. Not only is it aimed at beginners, but it also teaches you a lot about the important fundamentals of programming and computer science (e.g. data structures, recursion, etc.). It's very accessible, well-written, and easy to read. Plus, I found the examples engaging and interesting to work with. After that, if you really want to solidify your foundations in C, I'd recommend trying to moving on to The C Programming Language. It's a challenging book, so take it slowly. If you find yourself having too much trouble with it, I'd say you can just skip to Objective-C, and then come back to The C Programming Language later, once you've gained more familiarity with programming in general.
A lot of people will probably recommend The C Programming Language (a.k.a. "K&R") as your first book to read on C. No doubt it is a very well-written C book (and it's short too—only around 200 pages), but I'd say it'd be a little intimidating as a 12-year-old's first exposure to C: it's pretty dense and hardcore. You can tell that it's definitely aimed at an older audience with a strong background in computers/engineering. But nevertheless, if you already know the basics of programming, reading K&R will give you invaluable insight and understanding of C. You should definitely read it at some point in your programming endeavors.
Anyways, for Objective-C, if there's only one book I could recommend, it would most definitely be Cocoa Programming for Mac OS X, by Aaron Hillegass. It's really not that long (~400 pages or so, although I'd reckon that a lot of that is due to the number of illustrations in the book), and you can get some pretty cool projects up and running in an afternoon. It's very clear and easy to read, the examples are practical and interesting to follow, but most importantly, it's got this right blend of not being too intimidating while still managing to provide you with solid information. Plus, it'll teach you more than just Objective-C: I found that I had learned some very useful design patterns, for example, by learning how some of the components of Cocoa worked.
When I look at the title of this question, I am guessing you are 12.
I started programming when I was 13 (I am now 14).
I found that learning depends on what kind of a learner you are!
I hate reading, I have the attention span of a moth and I learn best from videos. Therefor, I am a "visual learner". Try to find out what kind of "learner" you are, then do it that way. Remember, the easiest way is the fastest.
PS, here is a little tip. It may be frustrating (aseptically at our age). If you get frustrated, just put it down for like 10 minutes. Then come back and do research on what your learning. Programming WILL get very frustrating at times.
EDIT:
By the way, I like to learn through video :p
Stanford University posts online the lectures, class notes, and assignments for CS193P (an iPhone development class). If you don't know C or Objective-C at all, it might be tough, but I highly recommend this if you intend to do iPhone development.
I think I've read every Cocoa and Objective-C book out there, and most enjoyed Aaron Hillegass' Cocoa Programming for Mac OS X.
I would take a look at The C Programming Language (K&R C). It's much less than 1000 pages and I think you'll find it well worth your while. As htw said, books do serve a purpose in that they provide a thorough and structured approach. K&R C in particular will give you real insight directly from the creators of C.
That's not to say you shouldn't Google things, read open source code, write little practice programs, etc. It all helps. Just remember to be patient. There's a lot out there.
Checkout out http://www.cprogramming.com/ or and online K&R type book
Don't be impatient; take your time. Follow tutorials, dissect short snippets of code, you'll get the hang of the language. Most importantly, write code yourself and learn from your bugs/errors.And follow Stack Overflow ;)
I've been where you are. It wasn't fun. This is what saved me:
(Apparently new users aren't allowed to post hyperlinks, so google for "steve summit C", use either the first or the third link, and then click "introductory C programming class notes")
It's a C class by a guy named Steve Summit. Super easy to follow, much easier than K&R, imo.
Also, it's free, and there aren't any ads. I loved it. It's how I learned C. I hope it'll do the same for you.
There is nothing so educational as a piece of code you can run and tweak. Code examples in books can be really bland and not very applicable. The exception to this rule was the Perl Cookbook which is jammed packed with really useful little snippets for your perl programs.
The topics (or 'idioms') in it were so useful and so applicable across languages that some smart folks have taken to replicating them in different languages. Each has a varied level of completeness, but it's interesting to see how different languages do the same things.
Take a look here http://pleac.sourceforge.net/ for nuggets of programming wisdom that you can shake a stick at. At the very least its interesting to see how simple things written in one language require reams of code in another.
Were I starting to learn programming again I would probably pick something easy and forgiving, a dynamic language, like Python, Ruby etc. Once you get your head around the basics in one of these (flow control, data structures etc) it will make learning C/Objective-C so much easier. Also you'll find that you'll want to write once-off tools and scripts to help you in your Objective-C development that would be tedious and time consuming to write in C but are a matter of lines in a modern dynamic language. Never hurts to have another tool in your belt.
Good luck
Honestly, I learned Java as my first programming language (I discovered it in high school and decided programming was fun and it was what i wanted to do)
I just now picked up Obj-C in a few weeks, reading a little bit from some books, but not a whole book, and using the internet a lot if i can't figure out the syntax (format/grammar of how the program should be structured and written) for something etc.
How fast you can pick up a language depends on how much you understand the fundamentals of programming. You will only get better at it with time and practice.
If you can understand the fundamentals of programming in general then you should be able to apply it to any language, the hard part is learning and remembering the syntax of different languages. Like in Java, you don't have to do memory allocations, but in C, C++ and Obj-C you do. I've never written a C or C++ program, but now that I've learned and written some programs in Obj-C (i've been making iPhone stuff, it is fun) I'm sure I could pick up C and C++ like it's nothing.
You don't have to learn C first in order to learn Obj-C is what i'm trying to say. But it never hurts to know multiple languages.
It is all about your level of understanding how a program works, how to structure one. I love objective-C because it is Object Oriented like Java so it was easier for me to understand and learn quickly, just had to get used to some of the differences in syntax
(I'm also getting close to graduating from college now so I'm surrounded by programming stuff, from procedural languages like ada to object oriented like java, and knowing the nitty gritty behind the scenes stuff that makes a program work, so understanding and learning a new language has gotten a lot easier for me, you start seeing how they relate and don't relate and it is cool)
It is great that you are starting so young. I'm sure you'll pick up on this stuff real fast, and if it is something you really enjoy, it will be even easier.
Good Luck! and have fun! programming can be so frustrating... like, spending 3 hours debugging when you find out it was because you if statement used a grater than instead of grater than or equal too or something like that. but, once you are done with the program, it is so rewarding, and then you just want to make it better and better haha.
I dunno if this helped at all, I hope it did, somehow...
=)
the way i learned quickest was to watch short video tutorials.
If you really want to start with C, I would start by just reading the first three or so chapters of C for Dummies, just to get a feel for how the language works. After that, I recommend going through web tutorials. Good web tutorials will have short code that explain specific functions, and the like.
As a 13-year old, though, I recommend starting with PHP. It's a simpler language to learn than C, but it's based off of C, so it won't be hard to make the transition, whenever you do so.
Different people have different preferred ways of learning. You can see that in the variety of responses above.
So how do you like to learn? Do you like to sit by yourself with a book and a computer? Do you like to sit in a classroom and absorb learning? Do you prefer set exercises, or mini-projects?
When I learn new programming languages, I find it helps me if I have a small application or problem to work on. I prefer to have a problem to work on. If you have a little project of your own that you always wanted to do, use that. If not, as someone above suggested, join a robotics group. Set up a web page and write some programs to do stuff for that.
Look on the web for programming challenges. Google has a fun one every year.
If you want an idea, write a sukoku checking program. Then later, write a sudoku solver!
I like to use a variety of books, rather than just sticking to one or two of the ones suggested above. Find a book whose style you like. Try a few from the library until you find one or two that really click for you.
Personally, I like O'Reilly Publishing books for their chatty and readable style. I learnt C from Deitel, which is more of a classroom style textbook, but it has lots of examples and discussion points.
As you work through examples on your computer, you might wonder how things change if you tweak the code. I learn a lot by first running the example code suggested in a text, but then changing it to see what happens. If I get what I expect, it's a sign that my understanding is pretty good. If I get something unexpected, I try to figure out how I misunderstood what I did.
One last suggestion. Why not start with Python rather than C? I hear that a lot of schools are teaching Python to their kids. The reasons I suggest this are:
Python is pretty easy. You don't have to lay out memory, declare variables and such. No tedious bookkeeping.
Python gives you a nice growth path. You can start off just writing script style programs, using the built in types like lists and dictionaries. Then you progress to using new modules as you need them, and advance into object-oriented coding using classes. There's some functional programming stuff in there too, which you can start learning once you have the basic mechanics of the language under control.
I just love visiting new parts of python all the time.
You can get a lot done in python. It comes with a whole lot of built in modules to do almost anything you like - email, web, xml, graphics, gui, etc.
:)
When I was learning to program in C, I found that Practical C Programming was a good resource. It's a very approachable book with lots of examples.
The fastest way in my view is through learn through websites.
Set a goal of what you want to do and start a simple project
Instead of reading too many books theoretically,google what you want to know to get it instantly as you go through your project.This way you get PRACTICAL knowledge.
Watch online videos as well.Check out my question on VIDEOS here
Ask whatever you don't understand on stackoverflow. We're here to help :)
Follow these steps and I can assure you that you will be a great programmer soon!
Cheers!
With others, I highly recommend Kernighan and Ritchie—perhaps the best language book ever written. I'd also recommend that you slow down and enjoy yourself: don't be wide and shallow; start out narrow and deep. If you like programming, you will want to master the craft rather than be in a hurry. This essay by Peter Norvig explains how not to be in such a rush.
P.S. I started programming at age 12 with APL/360. I had a blast and have been doing it ever since—35 years and counting. Good luck and don't forget to have fun!
By far the best way (and usually the fastest) to learn programming is to find a good mentor. That's easier said than done. But I think you'd be surprised how many people would be willing to help you out. My advice would be just don't be afraid to ask.
If I were you I would find a local FIRST robotics team and see if you can hang out for some of the coding. Odds are you'll be working on a similar problem and will have some support from people who have a decent amount of experience. That's what I would have done, anyway.
I started learning to program in Basic in about 1981 when I was 10. Not many years later it was 6502 assembly to try to get more speed out of a 1 MHz Apple IIe clone.
Pascal was a revelation in 1988 - programming without line numbers.
Modula-2, C, Eiffel, Miranda, Haskel, and Prolog at university as well as scripting in any number of languages.
C++ professionally for about 6 years.
C#, then Java, Ruby, and now back to C# for the last 18 months.
Python somewhere along the way.
My advice, pick the language that is best suited to the problem you need to solve today.
The first problem you have is to learn the basics ie how to break down a problem and express it in a clear and concise manner. I suggest you choose something other than C. I recommend Python as the online documentation is excellent and the libraries are great and you will spend more time writing interesting code and less time trying to figure out why your code stopped due to a segmentation fault.
When you've got the basic concepts under your belt, try some assembly and learn what's going on under the hood. If nothing else, you'll learn how fast CPUs really are. C is a good step after that. I also suggest you try Java or C# before Objective-C.
As to how long before moving to Objective-C, it really depends on how talented you are. If you're really good, then once you've learnt your 3rd or 4th language you'll can be more productive than most coders within 6 weeks of starting a new language (although changing language families (ie imperative, functional, object oriented) takes longer). If you're no good then don't expect to get past the first. Hopefully you make it into the first category.
In addition to whatever books and websites you end up using, you might consider looking around your area for local support groups. Many areas have a Linux user group or a group for Java or Ruby programming. Professional programmers use these groups to help each other with their programming problems, but the groups are generally friendly to young people and beginners. Don't feel embarrassed or awkward because of your age and inexperience. Most people will admire your initiative and curiosity and be happy to help you when you run into problems.
Assuming you have some basic programming knowledge, Cocoa Dev Central have a series of articles that explain basic C then Objective-C, in a somewhat-less-than-1000-pages way..
Learn C for Cocoa, then Learn Objective-C
Shouldn't take even an hour to go through. The articles don't cover anything remotely advanced, but if you're learning ObjC to write OS X applications, the ObjC bit is basically trivial, it's Cocoa that is difficult to learn!
If you want to learn Objectif-C to create iPhone application, don't waste your time on C and learn Objectif-C now, then a book on iPhone programming. It will be more than 1000 pages but if you want to program in your life, you have to be used to read these types of book.
I created an online interactive C tutorial, you can start using it without installing an IDE.
http://www.learn-c.org

How to develop *real life* oop skills?

I've been studying OOP for quite a while now and I have a good grasp of the theory. I read the Head First book on OOP and, while it reinforced a lot of the theory, I found the case studies to be somewhat trivial.
I find that I'm applying OOP principles to my code each day, but I'm not sure if I'm applying them correctly. I need to get to the point where I am able to look at my code and know whether I'm using inheritance appropriately, whether my object is cohesive enough, etc.
Does anyone have any good recommendations (books, online guides, blogs, walk-throughs, etc.) for taking the next step in developing solid OOP skills?
I am working primarily in .NET (visual basic), but I welcome suggestions that incorporate various platforms.
Read Refactoring by Martin Fowler, and apply it to your own work.
It will take you through a litany of malodorous characteristics of software code that describe how to detect improperly constructed classes, and even more importantly, how to fix them.
Consider looking into Design Patterns. Although it seems like they aren't commonly used in enterprise applications (I've seen them more commonly used in API's and Frameworks than embedded into enterprise code), they could be applied to make software simpler or more robust in a lot of situations if only developers knew how to apply them.
The key is to understand the design patterns first, then with experience you'll learn how to apply them.
There is a Head First book on design patterns that teaches the concept pretty simply, although if you want a book that really covers design patterns in detail, check out the Gang of Four design patterns book, which is basically what made design patterns mainstream and is referred to almost every time the topic is brought up.
Design patterns can be applied in pretty much any object-oriented language to some degree or another, although some patterns can be overkill or over engineering in some cases.
EDIT:
I also want to add, you should check out the book Code Complete 2. It's a very influential book in the world of software development. It covers a lot of different concepts and theories. I learn something new every time I read it. It's such a good book that if I read it every 6 months to a year, I look at it from a different perspective that makes me a better programmer just by re-reading it. No matter how much you might think you know, this book will make you realize just how little you really know. It's really a great book. I can't stress how much you should own this book.
If you already have the basics, I believe only experience will get you further. You say you are not sure if you are applying the principles correctly, but there is no one correct way. Code you write today, you'll look at in 6 months time, and wonder why you wrote it that way, and probably know of a better, cleaner way of doing it. I also guarantee that after 10 years, you'll still be learning new techniques and tricks. Don't worry too much about it, it will come, just read as much as you can, and try and apply what you read in small chunks.
I am currently half-way through the following book:
http://www.amazon.com/Applying-UML-Patterns-Introduction-Object-Oriented/dp/0131489062
I cannot recommend this book strongly enough in terms of learning a real-life, professional-grade, practical approach to drafting and applying a well-formed and iterative design strategy before diving into code.
I, too, read the "Head First" book and felt that I was much better off for having read it.
After having a few years of working-world experience, I now view the Craig Larman book that I am recommending to be a perfect "next step" for me.
About the Presence of "UML" in this Book Title:
Whether you have positive feelings or negative feelings about UML notation, please do not let that influence your decision to buy the book (ISBN 0131489062) in either direction.
The prominence of "UML" in the title is misleading. While the author does use and explain UML notation, these explanations are extremely well-woven into relevant design discussions, and at no time does this book read like a boring UML spec.
In fact, here is a quote taken directly from the book:
What's important is knowing how to think and design in objects, which is a very different and much more valuable skill than knowing UML notation. While drawing a diagram, we need to answer key questions: What are the responsibilities of the object? Who does it collaborate with? What design patterns should be applied? Far more important than knowing the difference between UML 1.4 and 2.0 !
This book at times seems like it is "speaking to" a lead architect or a project manager. What I mean to say by that is that it assumes that the reader has significant control over the planning and direction of a software project.
Nonetheless, even if you are only responsible for some very small piece of your company's projects and products, I would still recommend this book and encourage you to apply some "scaled down" modifications of the book's advice to your piece of the project.
My OOP epiphany came from Grady Booch's book, way long time ago. Suddenly I realized why objects were good.
While polymorphism is cool, encapsulation is 75% of why objects are cool. It is sort of like an interface: you see the buttons but not the wiring. Before objects, only the most disciplined coders kept their grubby fingers off the internal bits of other people's procedures (it was called "structured programming").
Object make it easy to Do the Right Thing. Inheritance and polymorphism are little bonuses.
One way to learn about objects is to read other peoples' code. I learned a lot by reading the source code for the Delphi VCL framework. Even just looking at the documentation for Java will help you see what a single object class should do and how it is designed to be used by other objects.
Start a project of your own and pay attention when you want to sub-class your own classes and find that you have to go back and break up some protected methods so you can override just one piece of a process instead of replacing all of it. See how ancestors talk to descendants by calling abstract functions. In other words, go make a lot of mistakes and learn from them.
Enjoy!
Frankly, re-reading old David Parnas papers on information hiding helps me get in the right state of mind. The case studies may not be directly applicable but you should be able to get some useful generalizations out of them.
My epiphany happened when I tried to implement a very OO problem (dynamically and recursively building SQL statements) in VB6. The best way to understand polymorphism or inheritance is to need it and not be able to use it.
One thing that will definitely help you is working on a well-known, respected open source project. Either dig through the source code and see how things are done or try to make some additions / modifications. You'll find that there isn't one style or one right answer for most problems, but by looking at several projects, you'll be able to get a wide view of how things can be done. From there, you'll begin to develop your own style and will hopefully make some contributions to open source in the process.
I think you have to attempt and fail at implementing OO solutions. That's how I did it anyway. What I mean by fail is that you end up writing smelly code while successfully delivering a working solution. After it's written you'll get a feel for where things didn't quite feel right. You may have some epiphanies, and/or you may go and hunt for a slicker solution from other programmers. Undoubtedly you'll implement some variation of standard design patterns by accident. In hindsight, a light will click on (oh! so that's what a visitor is for), and then understanding will accelerate.
As others have said, I think tooling through some good OO open source code is a good idea. So is working with more experienced programmers who would be willing to critique your work. However understanding comes through doing.
You might want to try to read (and write) some Smalltalk for a while. Squeak is a free implementation that can show you the power of a fully object-oriented environment (unlike java or .net). All library code source is included. The language itself is incredibly simple. You'll find that java and c# are slowly adding the features well-known to Smalltalk since 1980.
Tortoise HG is extrodanarily well designed piece of OO open source software (written in Python).
If you already understand the basics, building something from scratch in a fully object oriented language will be a good step in fully understanding OOP software architecture. If you don't know Python, Python Essential Reference will take you through the language in full in a few days to a week.
After you understand the language take a look through the software above and you'll have all sorts of epiphanies.
To understand basically anything thoroughly, you need to have a decent knowledge of at least one abstraction level above and one level below it. In the case of OO, others have mentioned design patterns as the layer above OO. This helps a lot to illustrate why OO is useful.
As far as the layer below OO, try to play around with higher-order functions/late binding for a while and get a feel for how these relatively simple constructs are used. Also, try to understand how OO is implemented under the hood (vtables, etc.) and how it can be done in pure C. Once you grok the value of using higher order functions and late binding, you'll quickly realize that OO is just a convenient syntax for passing around a set of related functions and the data they operate on.