This is a generic question - i know a bit of perl and python and i am looking in to learn programming so that once i get a hang of it i can start developing apps and then websites.
I request you to give me algorithm(steps :)) that what should be my approach towards learning it.
I have posted small questions on perl/python and i have recieved great help from everyone.
Note:- i am not in a hurry to learn i know it takes time and thats fine.
Please give any suggestions you think are valid(Please dun push me to learn Lisp,Haskell - i am a beginner)
Step 1. Read
Step 2. Implement
Step 3. Repeat Step 1 until ur frustrated.
Simple Algo
Start with a good book that covers control structures, etc. (two I would recommend include Head First Programming, or learning to program (which is a Ruby book).
After that, try out some basic stuff to learn your syntax, control structures, logic, etc. - some good sites for this are:
Project Euler
Coding Dojo
Code Kata (pragpub)
Then, move up from there (at that point you may want more framework specific stuff - MVC, Rails, etc.).
On a side note - language is largely irrelevant. I'm mentoring an apprentice developer at work now (in C# but he's also looking at some Python), and in our last coding session, we wrote very little code, but spent a ton of time chewing through edge cases in a code kata.
(An addendum)
Once you're past basic control structures and syntax, you're going to find the toughest parts are design, abstraction, problem solving, etc. - so for those some good ways to pick up those skills include:
Getting a good mentor (even a virtual one).
Looking at LOTS of code. If you are not in a dev shop, look at an opensource project you're interested in to see how other people code.
Contribute to OSS
Start small, and build something for yourself (I'm always partial to building your own blog site - like a Jedi has to build their own lightsaber ;)
Have fun!
In Episode 78 of the Joel & Jeff podcast one of the Doctype / Litmus guys states that you would never want to build a spider in ruby. Would anyone like to guess at his reasoning for this?
Just how fast does a crawler need to be, anyhow? It depends upon whether you're crawling the whole web on a tight schedule, or gathering data from a few dozen pages on one web site.
With Ruby and the nokogiri library, I can read this page and parse it in 0.01 seconds. Using xpath to extract data from the parsed page, I can turn all of the data into domain specific objects in 0.16 seconds. All 223 rows.
I am running into fewer and fewer problems where the traditional constraints (cpu/memory/disk) matter. This is an age of plenty. Where resources are not a constraint, don't ask "what's better for the machine." Ask "what's better for the human?"
In my opinion it's just a matter of scale. If you're writing a simple scraper for your own personal use or just something that will run on a single machine a couple of times a day, then you should choose something that involves less code/effort/maintenance pains. Whether that's ruby is a different question (I'd pick Groovy over Ruby for this task => better threading + very convenient XML parsing). If, on the other hand, you're scraping terabytes of data per day, then throughput of your application is probably more important than shorter development time.
BTW, anyone that says that you would never want to use some technology in some context or another is most probably wrong.
You wouldn't get the desired performance out of Ruby. See the referenced link: http://blog.dhananjaynene.com/2008/07/performance-comparison-c-java-python-ruby-jython-jruby-groovy/
While performance tests like these should be taken with a grain of salt, there is a considerable difference between Ruby and the top(in speed) languages.
Edit: Shame on me for answering a loaded question. All-in-all choosing a language is a series of trade offs spanning from performance to personal preferences on what you are efficient in. The beauty of programming is that all of these languages are available for you to use, so you can test what works best for the requirements of your project. My recommendation is to experiment and see what works best for you.
What OG said. In simpler terms, Ruby is dog slow and if you're looking to get a lot done per unit time, it's the wrong choice of language.
Having been a hobbyist programmer for 3 years (mainly Python and C) and never having written an application longer than 500 lines of code, I find myself faced with two choices :
(1) Learn the essentials of data structures and algorithm design so I can become a l33t computer scientist.
(2) Learn Qt, which would help me build projects I have been itching to build for a long time.
For learning (1), everyone seems to recommend reading CLRS. Unfortunately, reading CLRS would take me at least an year of study (or more, I'm not Peter Krumins). I also understand that to accomplish any moderately complex task using (2), I will need to understand at least the fundamentals of (1), which brings me to my question : assuming I use C++ as the programming language of choice, which parts of CLRS would give me sufficient knowledge of algorithms and data structures to work on large projects using (2)?
In other words, I need a list of theoretical CompSci topics absolutely essential for everyday application programming tasks. Also, I want to use CLRS as a handy reference, so I don't want to skip any material critical to understanding the later sections of the book.
Don't get me wrong here. Discrete math and the theoretical underpinnings of CompSci have been on my "TODO: URGENT" list for about 6 months now, but I just don't have enough time owing to college work. After a long time, I have 15 days off to do whatever the hell I like, and I want to spend these 15 days building applications I really want to build rather than sitting at my desk, pen and paper in hand, trying to write down the solution to a textbook problem.
(BTW, a less-math-more-code resource on algorithms will be highly appreciated. I'm just out of high school and my math is not at the level it should be.)
Thanks :)
This could be considered heresy, but the vast majority of application code does not require much understanding of algorithms and data structures. Most languages provide libraries which contain collection classes, searching and sorting algorithms, etc. You generally don't need to understand the theory behind how these work, just use them!
However, if you've never written anything longer than 500 lines, then there are a lot of things you DO need to learn, such as how to write your application's code so that it's flexible, maintainable, etc.
For a less-math, more code resource on algorithms than CLRS, check out Algorithms in a Nutshell. If you're going to be writing desktop applications, I don't consider CLRS to be required reading. If you're using C++ I think Sedgewick is a more appropriate choice.
Try some online comp sci courses. Berkeley has some, as does MIT. Software engineering radio is a great podcast also.
See these questions as well:
What are some good computer science resources for a blind programmer?
https://stackoverflow.com/questions/360542/plumber-programmers-vs-computer-scientists#360554
Heed the wisdom of Don and just do it. Can you define the features that you want your application to have? Can you break those features down into smaller tasks? Can you organize the code produced by those tasks into a coherent structure?
Of course you can. Identify any 'risky' areas (areas that you do not understand, e.g. something that requires more math than you know, or special algorithms you would have to research) and either find another solution, prototype a solution, or come back to SO and ask specific questions.
Moving from 500 loc to a real (eve if small) application it's not that easy.
As Don was pointing out, you'll need to learn a lot of things about code (flexibility, reuse, etc), you need to learn some very basic of configuration management as well (visual source safe, svn?)
But the main issue is that you need a way to don't be overwhelmed by your functiononalities/code pair. That it's not easy. What I can suggest you is to put in place something to 'automatically' test your code (even in a very basic way) via some regression tests. Otherwise it's going to be hard.
As you can see I think it's no related at all to data structure, algorithms or whatever.
Good luck and let us know
I must say that sitting down with a dry old textbook and reading it through is not the way to learn how to do anything effectively, even if you are making notes. Doing it is the best way to learn, using the textbooks as a reference. Indeed, using sites like this as a reference.
As for data structures - learn which one is good for whatever situation you envision: Sets (sorted and unsorted), Lists (ArrayList, LinkedList), Maps (HashMap, TreeMap). Complexity of doing basic operations - adding, removing, searching, sorting, etc. That will help you to select an appropriate library data structure to use in your application.
And also make sure you're reasonably warm with MVC - i.e., ensure your model is separate from your view (the QT front-end) as best as possible. Best would be to have the model and algorithms working on their own, and then put the GUI on top. Or a unit test on top. Etc...
Good luck!
It's like saying you want to move to France, so should you learn french from a book, and what are the essential words - or should you just go to France and find out which words you need to know from experience and from copying the locals.
Writing code is part of learning computer science. I was writing code long before I'd even heard of the term, and lots of people were writing code before the term was invented.
Besides, you say you're itching to write certain applications. That can't be taught, so just go ahead and do it. Some things you only learn by doing.
(The theoretical foundations will just give you a deeper understanding of what you wind up doing anyway, which will mainly be copying other people's approaches. The only caveat is that in some cases the theoretical stuff will tell you what's futile to attempt - e.g. if one of your itches is to solve an NP complete problem, you probably won't succeed :-)
I would say the practical aspects of coding are more important. In particular, source control is vital if you don't use that already. I like bzr as an easy to set up and use system, though GUI support isn't as mature as it could be.
I'd then move on to one or both of the classics about the craft of coding, namely
The Pragmatic Programmer
Code Complete 2
You could also check out the list of recommended books on Stack Overflow.
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I've had several false starts in the past with teaching myself how to program. I've worked through several books (mostly C and Python), and end up just learning the syntax without feeling as though I could sit down and actually write a program for myself. When I try to look through the source trees of a project on Codeplex or Sourceforge, I never seem to know where to start reading the code -- the dependencies seem to go in all directions.
I feel as though I'm not learning programming the way it's done "on the street," so I figured I'd take a different approach to asking how a newbie should learn how to code. If you had to learn programming all over again, what are the things you wouldn't do? What did you spend time doing that you now know wasted you weeks or months?
Where I see beginners wasting weeks or months is typing at the keyboard. The computer is very responsive and will cheerfully chew up hours of your time in the edit-compile-run cycle. If you are learning you will save many hours if
You plan out your design on paper before you approach a computer. It doesn't matter what design method you pick or if you have never heard of a design method. Just write down a plan while your brain is fully engaged and not distracted by the computer.
When code will not compile or will not produce the right answer, if you can't fix it in five minutes, walk away from the computer. Go think about what's happening. Print out your code and scribble on it until you believe it's right.
These are just devices for helping to implement the simple but difficult old advice to think before you code.
When I was learning, I solved countless problems on the 15-minute walk from the computing center to my home. Sadly, with modern PCs we don't get that 15 minutes :-) If you can learn to take it anyway, you will become a better programmer, faster.
I certainly wouldn't start by looking at "real" software projects. Like you say, it's too hard to know where to start. That's largely because large projects are more about their large-scale design than about the individual algorithms or about program flow; for one thing, you're probably looking at a complex GUI application with multi-threading, etc. There isn't really anywhere to "start" looking at the code.
The best way to learn programming is to have a problem you want (need) to solve, and then going about solving it. But most importantly, WRITE CODE. When you read programming books, do ALL the exercises. Make sure you did them right. There's no substitute for writing code. No substitute for screwing up and then fixing it.
Stack Over F.. wait no, heh.
The biggest time-sinks for me are generally in respect to "finding the best answer." I often find that I will run into a problem that I know how to solve but feel that there is a better solution and go on the hunt for it. It is only hours/days later that I come to my senses and realize that I have 7 instances of Firefox, each containing at least 5 tabs sprawled out across 46" of monitor space that I realize that I've been caught in the black hole that is the pursuit of endless knowledge.
My advice to you, and myself for that matter, is to become comfortable with notion of refractoring. Essentially what this means (incase you are are not familiar with the term) is you come up with a solution for a problem and go with it, even if there is quite likely a better way of doing it. Once you have finished the problem, or even the program, you can then revisit your methodology, study it, and figure out where you can make changes to improve it.
This concept has always been hard for me to follow. In college I preferred to to write a paper once, print, and turn it in. Writing code can be thought of very similarly to writing a paper. Simply putting the pen to the pad and pushing out whats on your mind may work - but when you look back over it with a fresh pair of eyes you will, without question, see something you will wish you had done differently.
I just noticed you talked about reading through source trees of other people's projects. Reading other people's code is a wonderful idea, but you must read more selectively. A lot of open-source code is hard to read and not stuff you should emulate anyway. So avoid reading any code that hasn't been recommended by a programmer you respect.
Hint: Jon Bentley, Brian Kernighan, Rob Pike, and P. J. Plauger, who are all programmers I respect, have published a lot of code worth reading. In books.
The only way to learn how to program is to write more code. Reading books is great, but writing / fixing code is the best way to learn. You can't learn anything without doing.
You might also want to look at this book, How to Design Programs, for more of a perspective on design than details of syntax.
The only thing that I did that wasted weeks or months was worry about whether or not my designs were the best way to implement a particular solution. I know now that this is known as "premature optimization" and we all suffer from it to one degree or another. The right way to learn programming is to solve a problem, measure your solution to make sure it performs good enough, then move on to the next problem. After some time you'll have a pile of problems you've solved, but more importantly, you'll know a programming language.
There is excellent advice here, in other posts. Here are my thoughts:
1) Learn to type, the reasons are explained in this article by Steve Yegge. It will help more than you can imagine.
2) Reading code is generally considered a hard task. So, it is better to get an open source project, compile it, and start changing it and learn that way, rather than reading and trying to understand.
I can understand the situation you're in. Reading through books, even many will not make you programmer. What you need to do is START PROGRAMMING.
Actually programming is a lot like swimming in my opinion, even if you know only a little syntax and even lesser amount of coding techniques, start coding anyway. Make a small application, a home inventory, an expense catalog, a datesheet, a cd cataloger, anything you fancy.
The idea is to get into the nitty-gritties of it. Once you start programming you'll run into real-world problems and your problem solving skills will develop as you combat them. That's how you become a better programmer everyday.
So get into the thick of it, and swim right through... That's how you'll make it.
Good luck
I think this question will have wildly different answers for different people.
For myself, I tried C++ at one point (I was about ten and had already been programming for a while), with a click-and-drag UI builder. I think this was a mistake, and I should have gone straight to C and pointers and such. Because I'm just that kind of person.
In your case, it sounds like you want to be led down the right path by someone and feel a bit timid about jumping in and doing something by yourself. (You've read several books and now you're asking what not to do.)
I'll tell you how I learned: by doing plenty of fun, relatively short projects, steadily growing in difficulty. I began with QBasic (which I think is still a great learning tool) and it was there where I developed most of my programming skills. They have of course been expanded and refined since that time but I was already capable of good design back in those days.
The sorts of projects you could take on depend on your interests; if you're mathematically inclined you might want to try a prime number generator or projecting 3D points onto the screen; if you're interested in game design then you could try cloning pong (easy) or minesweeper (harder); or if you're more of a hacker you might want to make a simple chat program or file encryption software.
Work on these projects on your own, and don't worry about whether you're doing things the "right" way. As long as you get it to work, you've learned many things. Some time after you've completed a project you may want to revisit it and try to do it better, or just see how other people have done that sort of thing.
Given the way you seem to want to be led along, perhaps you should find yourself a mentor.
Do not learn how to use pointers and how to manually manage memory. You mentioned C, and I spent plenty of time trying to fix bugs that were caused by mixing *x and &x. This is evil...
Find some problem to solve, write or draw a sketch of an algorithm solving the problem, then try to write it. Either use Python (which is much more friendly for beginners) or use C with statically allocated memory only. And use books/tutorials. They offer multiple excercises with solutions, so you can compare yours with them and see other approaches.
Once you'll feel that you can actually write something simple, see some book/tutorial for Object Oriented Design. It's not the best the world has to offer, but it might turn out to be intuitive. If not, check the functional programming (like LISP, Scheme or Haskell languages), or programming in logic (like Prolog). Maybe those will suit you better.
Also - find some mate. A person you can talk to about coding, code maintenance and design. Such person is worth even more than a book.
To all C fans: The C language is great, really. It allows memory usage optimization to the extent impossible in high-level languages as Python or Ruby. The compiled code is also very fast, and is the only choice for RTOS, or modern 3D games engine. But this is not a good entry point for a beginner, that's what I believe.
Oh, and good luck to you! And don't be ashamed to ask! If you don't ask, the answer is much harder to find.
Assuming you have decent math skills try http://projecteuler.net/ It presents a series of problems to solve of increasing dificulty that should be solvible by writing short programs. This should give you experience in solving specific problems with out getting lost in the details of open source projects.
After basic language syntax, you need to learn design. Which is hard. This book may help.
I think you should stop thinking you've wasted time so far-- instead I think you're education is just incomplete, and you've taken a step you're not really ready for. It sounds like the books you've read are useful, you're learning the intricacies of the language. It sounds like you're just not accustomed to the tools you'd use then to package that code together so it runs.
Some books cover that focus on topics like language syntax, design patterns, algorithms and data structures will never mention the tools you need to actual apply that information. These books are great but if its all you've touched I think it would explain your situation.
What development environment are you using? If you're developing for windows you really should be proficient with creating projects, adding code, running and debugging in Visual Studio. You can download Visual Studio Express for free from Microsoft.
I recommend looking for tutorial like books that actually step you through the UI of development environment you are using. Look for actual screenshots with dropdown menus. Look at what the tutorials walk you through, and if its something you don't know how to do consider buying that book. Preferably it will have code you can copy'n'paste in, not code you write yourself.
I personally don't like these books as I can anticipate how to do new things in VS based on how I'd do other things. But if you're training is incomplete from a tools-usage perspective this could move you in the right direction.
It is probably harder to find these types of tutorial books for Python or C development. There is an overabundance of them for .Net development though.
As someone who has only been working as a programmer for 6 months, I might not be the best person to help you get going, but since it wasn't that long ago when I knew next to nothing, its quite fresh in my mind.
When I started my current job programming wasn't going to be part of my job description but when the opportunity came up to do some programming on the side, I couldn't pass it up.
I spent about 1 month doing tutorials on About.com's Delphi section. As much as people diss about.com, Zarko Gajic's tutorials were simple to understand and easy to follow. Once I had a basic knack of the language and the IDE, I jumped straight into a project exporting accounting data for a program called "Adept". Took me a while but I got there...
The biggest help for me was taking on a personal project. I developed an IRC bot in Java for a crappy 2D game called Soldat. I learnt a lot by planning out and coding my own project.
Now I'm pretty comfortable with Delphi Pascal, SQL, C# and Java. I think, once you get the hang of one OOP language, you can learn the syntax of another language, and it gets a lot easier to catch on.
Perhaps start with a small existing project, and find some thing within it that handles some core part of what it does - then with a debugger, step through it and follow what it's doing from the point where you ask it to do that thing for you.
This helps you in a number of ways. You start to better grasp all of the various things that are touched by the code as it attempts to complete its request. Also, you learn invaluable debugging techniques which it seems like far too many developers lack - while you can often eventually discover what is wrong either with repeated printf() (or equivalent) calls, if you can debug you can solve issues an order of magnitude faster.
I have found that conceptually, a great mental model for understanding programming in the abstract is a pattern of data flow. When a user manipulates data, how is it altered by a program for digestion and storage? How is it transformed to re-present to the user in a form that makes sense to them? Fundamentally code is about transformation of data, and all code can be broken down into constructs of various sizes whose purpose is to alter data in one way or another, bugs forming around the mismatch between what the programmer was expecting from the data, how high level libraries the coder is using treat the data, and how the data actually arrives. Following code with a debugger helps you fully understand this transformation in action by observing changes as they occur.
Standard answer is to make something; picking an easy language to do it in is good, but not essential. It's more the working out stuff in your own head, fixing it because it won't work, that really teaches you. For me, this always happens when I try my eternal dream projects (games) which I never finish but always learn from.
I think the thing I would avoid is learning a language in isolated snippets that don't really hang together but just teach various facets of a particular language. As others have said, the really hard and important thing is to learn design. I think the best way to do this is through a tutorial that walks you through creating an actual application, teaching design along the way. That way you can learn why certain decisions are made and learn how to accomplish what's needed to implement the design choices.
For example, I found Agile Web Development with Rails to be a really easy way to learn Ruby on Rails, much better than simply reading a Ruby manual or even poking my way around scattered web tutorials.
Another thing that I would avoid is developing code in isolation, that is, not having people look at it as I go along. Getting feedback from a mentor will help keep you on the right track with respect to the choices you are making and the correct use of language idioms.
Find a problem in your life or something you do that you just feel could be more efficient and write a small solution to it. It might just be a single script but you will gain much more confidence in your abilities when you start to see useful results of your work. You will also be more motivated to finish it as you are interested in using the solution. Start simple and small and then gradually move up to bigger projects.
And as your working on a small project, focus on building everything with quality. I think this is lost on some programmers who feel that their software is more impressive if it contains a ton of features but usually those features aren't well done or usable. If you focus on building quality solutions to real problems you'll be a fantastic programmer.
Good luck!
Work on projects/problems that you already know how to solve partially
You should read Mike clark's article : How I Learned Ruby. Essentially, he used the test framework for Ruby to exercise different elemnents of the languages.
I used this technique to learn python and it was very, very helpful. Not only did i learn the language, but I was very proficient in the test framework for Python at the end of the excercise. Once you have the basics you can start reading code and then working on building some larger project.