Search Results

Search found 14176 results on 568 pages for 'functional programming'.

Page 75/568 | < Previous Page | 71 72 73 74 75 76 77 78 79 80 81 82  | Next Page >

• What is this called?

  - by robertlewis2001

  I'm hoping there's a book or something out there for me to get... If I have a class that has Collection as an instance variable, what is that method of coding called? A design pattern? If so, where can I find more information on it? As I've been working with this mentor, he's really helped me understand my programming weakness and that weakness is thinking in terms of collections or relationships between objects. It just seems so difficult for me right now and I need to read to become smarter. My mentor is a great guy, but he gets frustrated when I start asking lots of questions, so I'm starting to feel like I need to learn more on my own. public class Evaluation { private List<Criterion> criterion = null; public Evaluation() { criterion = new List<Criterion>(); } }

  Read the article

• Particles are not moving correctly [closed]

  - by cr33p

  I want to make a particle explosion, after something gets destroyed, but somehow only one line of mixed colors show up on the screen. Here's the header: http://pastebin.com/JW5bPLj2 Here's the source: http://pastebin.com/KHmFqytD I don't get what's wrong, as it's nearly the same as in "Programming Linux Games" Can somebody help me fix that? PS: "Uint32 delta" is needed to update the pixels based on time. PSS: Maybe I should add that it's programmed in C and includes SDL. EDIT: Found the problem. It was the "drawParticles" function. The problem was, that I passed a double to "offset" (as particles[i].x, etc are all doubles). So I ended up with values like ~MAX_INT because I didn't cast the doubles properly to ints.

  Read the article

• Why is Prolog associated with Natural Language Processing?

  - by kyphos

  I have recently started learning about NLP with python, and NLP seems to be based mostly on statistics/machine-learning. What does a logic programming language bring to the table with respect to NLP? Is the declarative nature of prolog used to define grammars? Is it used to define associations between words? That is, somehow mine logical relationships between words (this I imagine would be pretty hard to do)? Any examples of what prolog uniquely brings to NLP would be highly appreciated.

  Read the article

• Game Development Resources? [closed]

  - by stas

  I want to make an iPhone game and I was wondering if somebody could point me to some resources. Before you rage and close this, I am not looking for just a tutorial on programming, I could just google that. I need to find a tutorial on how to actually make a game, as in how to organize your code, what type of methods to run in separate threads, how to manage these threads in a game, etc. I already know everything I need; I can write a physics engine from scratch, I can write a 3D graphics pipeline from scratch, and so on. What I cannot figure out is how to combine all of this knowledge into correctly and efficiently making a game. Obviously for this one would probably go to college, but seeing as I am still in high school, that is not an option. If anyone would know some tutorials or resources, any pointers would be appreciated.

  Read the article

• Root directory of the kernel

  - by user592748

  A newbie here. I am trying to set up Eclipse for Linux Kernel Programming. The guide says set the project location as the root directory of the kernel. Where's the root directory of the kernel now? According to Linux file hierarchy system, it lists /lib as the root directory for shared libraries and kernel modules. I also see /lib32 and /lib64. However, I tried proceeding selecting /lib as the location and eclipse doesn't allow me to create the project.

  Read the article

• Confused about my future. Doubt about .Net or Java way.

  - by dotNET

  I'm very confused about choosing the programming langage to follow in the next step of my life. I'm right now so familiar with C++, VB.NET and PHP, but to jump to a higher level I must choose between JEE(JSP, Servlets, JSF, Spring, EJB, Struts, Hibernate,...) and .NET(ASP.NET, C#). Because I cant learn them at the same time. And you realize that, when I mentioned JEE a lot of things comes to the head. In my personnal experience I prefere the .NET, but Java seems to be a better choice. believe me, i'm not writing a subjective topic. I just want to know what must I follow to get succes in my life. The question here is : Is there any things that can be done with Java, and cannot be done with .NET. Is there any chances that I can follow the uncounted number of frameworks that are always in developpement. ... (also something not said) ?

  Read the article

• using static methods and classes

  - by vedant1811

  I know that static methods/variables are associated with the class and not the objects of the class and are useful in situations when we need to keep count of, say the number of objects of the class that were created. Non-static members on the other hand may need to work on the specific object (i.e. to use the variables initialized by the constructor) My question what should we do when we need neither of the functionalities? Say I just need a utility function that accepts value(s) and returns a value besed solely on the values passed. I want to know whether such methods should be static or not. How is programming efficiency affected and which is a better coding practice/convention and why. PS: I don't want to spark off a debate, I just want a subjective answer and/or references.

  Read the article

• How compilers know about other classes and their properties?

  - by OnResolve

  I'm writing my first programming language that is object orientated and so far so good with create a single 'class'. But, let's say I want to have to classes, say ClassA and ClassB. Provided these two have nothing to do with each other then all is good. However, say ClassA creates a ClassB--this poses 2 related questions: -How would the compiler know when compiling ClassA that ClassB even exists, and, if it does, how does it know it's properties? My thoughts thus far had been: instead of compiling each class at a time (i.e scan, parse and generate code) each "file (not really file, per se, but a "class") do I need to scan + parse each first, then generate code for all?

  Read the article

• How to begin serious game development (in C++) [closed]

  - by Rondogiannis Aristophanes

  I would like to start developing games. I have tried before Game Maker 8, which was a very easy way to start creating games, if you were new in game development. Then, I tried Unity 3D, which was a much more serious and complete tool to create computer-games, and required some experience. And now, I would like to start creating games, and don't use any special environment or developer, but just code (in C++ preferably). So, here is my question: from where should I begin, if I would like to start programming games? Thanks in advance. Note: I work in ubuntu 10.04, I can also use windows 7, but I prefer ubuntu.

  Read the article

• What is the difference from the push and pull development models?

  - by michelpm

  I was reading Extreme Programming Explained, Second Edition and in the chapter 11 "The Theory of Constraints" the authors talk about the old and obsolete "push" development model and the XP way, the "pull" development model. It looks like a quite important concept, but it takes only a very small paragraph and two images that are mere illustrations of the "waterfall" and iterative process, nothing specific about these models except by the image caption. I searched and it doesn't go any further about it in the rest of the book. I couldn't find any further explanations or discussions about it in the Internet either. If the only difference about those is that one is "waterfall" and the other is iterative, them why push and why pull? Does anyone understand what is really the difference between those two and give some good examples?

  Read the article

• Need to organize words based on their components, any other way aside from brute force?

  - by Lathan

  I'm not sure if this process has a name. I have some words (about 9,000). They are in Japanese, but I'll try to explain this using English words. I want to categorize the words by the components (in English, letters). A B C act bar play This should create: A: play B: bar C: act Now, 'a' appears in all 3 words, but I want to make sure that each category (letter) has at least word. Now, it would make sense to delete a word after it's used, but there are a few cases where 2 letters make up one word and that's each letter's only word--so I'd like to account for that somehow. Is there an approach for solving this aside from brute force? Dynamic programming perhaps? Even a name for this process (if it exists) would be great.

  Read the article

• What do you need to master a language and its technology? [closed]

  - by LongTTH

  Possible Duplicate: how to really master a programming language Let say about Java(just a sample, you can talk about C#, PHP, C++ ... it's just similar) and 10 (ten) levels, 1 is newbie and 10 is master. How can you identify someone at which level based on his knowledge? I do not tend to compare languages, I do tend to know what indicate a master or a newbie in a language and its (language's) based technology. Yeah, I know there aren't on earth a language stand alone, it always come with a technology with it. Let say in Java, you can memorize all of its keyword and syntax in just few days, but to know it (I mean do something with it effectively), you must read the Oracle (Sun) javadoc many many times (I'm not mention the 3rd party product yet).

  Read the article

• Would you use (a dialect of) LISP for a real-world application? Where and why?

  - by Anto

  LISP (and dialects such as Scheme, Common LISP and Clojure) haven't gained much industry support even though they are quite decent programming languages. (At the moment though it seems like they are gaining some traction). Now, this is not directly related to the question, which is would you use a LISP dialect for a production program? What kind of program and why? Usages of the kind of being integrated into some other code (e.g. C) are included as well, but note that it is what you mean in your answer. Broad concepts are preferred but specific applications are okey as well.

  Read the article

• Are lambda expressions/delegates in C# "pure", or can they be?

  - by Bob

  I recently asked about functional programs having no side effects, and learned what this means for making parallelized tasks trivial. Specifically, that "pure" functions make this trivial as they have no side effects. I've also recently been looking into LINQ and lambda expressions as I've run across examples many times here on StackOverflow involving enumeration. That got me to wondering if parallelizing an enumeration or loop can be "easier" in C# now. Are lambda expressions "pure" enough to pull off trivial parallelizing? Maybe it depends on what you're doing with the expression, but can they be pure enough? Would something like this be theoretically possible/trivial in C#?: Break the loop into chunks Run a thread to loop through each chunk Run a function that does something with the value from the current loop position of each thread For instance, say I had a bunch of objects in a game loop (as I am developing a game and was thinking about the possibility of multiple threads) and had to do something with each of them every frame, would the above be trivial to pull off? Looking at IEnumerable it seems it only keeps track of the current position, so I'm not sure I could use the normal generic collections to break the enumeration into "chunks". Sorry about this question. I used bullets above instead of pseudo-code because I don't even know enough to write pseudo-code off the top of my head. My .NET knowledge has been purely simple business stuff and I'm new to delegates and threads, etc. I mainly want to know if the above approach is good for pursuing, and if delegates/lambdas don't have to be worried about when it comes to their parallelization.

  Read the article

• How to iterate over modifed std::map values?

  - by Frank

  I have an std::map, and I would like to define an iterator that returns modified values. Typically, a std::map<int,double>::iterator iterates over std::pair<int,double>, and I would like the same behavior, just the double value is multiplied by a constant. I tried it with boost::transform_iterator, but it doesn't compile: #include <map> #include <boost/iterator/transform_iterator.hpp> #include <boost/functional.hpp> typedef std::map<int,double> Map; Map m; m[100] = 2.24; typedef boost::binder2nd< std::multiplies<double> > Function; typedef boost::transform_iterator<Function, Map::value_type*> MultiplyIter; MultiplyIter begin = boost::make_transform_iterator(m.begin(), Function(std::multiplies<double>(), 4)); // now want to similarly create an end iterator // and then iterate over the modified map The error is: error: conversion from 'boost ::transform_iterator< boost::binder2nd<multiplies<double> >, gen_map<int, double>::iterator , boost::use_default, boost::use_default >' to non-scalar type 'boost::transform_iterator< boost::binder2nd<multiplies<double> >, pair<const int, double> * , boost::use_default, boost::use_default >' requested What is gen_map and do I really need it? I adapted the transform_iterator tutorial code from here to write this code ...

  Read the article

• Learning Haskell maps, folds, loops and recursion

  - by Darknight

  I've only just dipped my toe in the world of Haskell as part of my journey of programming enlightenment (moving on from, procedural to OOP to concurrent to now functional). I've been trying an online Haskell Evaluator. However I'm now stuck on a problem: Create a simple function that gives the total sum of an array of numbers. In a procedural language this for me is easy enough (using recursion) (c#) : private int sum(ArrayList x, int i) { if (!(x.Count < i + 1)) { int t = 0; t = x.Item(i); t = sum(x, i + 1) + t; return t; } } All very fine however my failed attempt at Haskell was thus: let sum x = x+sum in map sum [1..10] this resulted in the following error (from that above mentioned website): Occurs check: cannot construct the infinite type: a = a -> t Please bear in mind I've only used Haskell for the last 30 minutes! I'm not looking simply for an answer but a more explanation of it. Thanks in advanced.

  Read the article

• Printing a field with additional dots in haskell

  - by Frank Kluyt

  I'm writing a function called printField. This function takes an int and a string as arguments and then then prints a field like this "Derp..." with this: printField 7 "Derp". When the field consists of digits the output should be "...3456". The function I wrote looks like this: printField :: Int -> String -> String printField x y = if isDigit y then concat(replicate n ".") ++ y else y ++ concat(replicate n ".") where n = x - length y This obviously isn't working. The error I get from GHC is: Couldn't match type `[Char]' with `Char' Expected type: Char Actual type: String In the first argument of `isDigit', namely `y' In the expression: isDigit y In the expression: if isDigit y then concat (replicate n ".") ++ y else y ++ concat (replicate n ".") I can't get it to work :(. Can anyone help me out? Please keep in mind that I'm new to Haskell and functional programming in general.

  Read the article

• How to use boost::transform_iterator to iterate over modifed std::map values?

  - by Frank

  I have an std::map, and I would like to define an iterator that returns modified values. Typically, a std::map<int,double>::iterator iterates over std::pair<int,double>, and I would like the same behavior, just the double value is multiplied by a constant. I tried it with boost::transform_iterator, but it doesn't compile: #include <map> #include <boost/iterator/transform_iterator.hpp> #include <boost/functional.hpp> typedef std::map<int,double> Map; Map m; m[100] = 2.24; typedef boost::binder2nd< std::multiplies<double> > Function; typedef boost::transform_iterator<Function, Map::value_type*> MultiplyIter; MultiplyIter begin = boost::make_transform_iterator(m.begin(), Function(std::multiplies<double>(), 4)); // now want to similarly create an end iterator // and then iterate over the modified map The error is: error: conversion from 'boost ::transform_iterator< boost::binder2nd<multiplies<double> >, gen_map<int, double>::iterator , boost::use_default, boost::use_default >' to non-scalar type 'boost::transform_iterator< boost::binder2nd<multiplies<double> >, pair<const int, double> * , boost::use_default, boost::use_default >' requested What is gen_map and do I really need it? I adapted the transform_iterator tutorial code from here to write this code ...

  Read the article

• Invoking code both before and after WebControl.Render method

  - by Dirk

  I have a set of custom ASP.NET server controls, most of which derive from CompositeControl. I want to implement a uniform look for "required" fields across all control types by wrapping each control in a specific piece of HTML/CSS markup. For example: <div class="requiredInputContainer"> ...custom control markup... </div> I'd love to abstract this behavior in such a way as to avoid having to do something ugly like this in every custom control, present and future: public class MyServerControl : TextBox, IRequirableField { public IRequirableField.IsRequired {get;set;} protected override void Render(HtmlTextWriter writer){ RequiredFieldHelper.RenderBeginTag(this, writer) //render custom control markup RequiredFieldHelper.RenderEndTag(this, writer) } } public static class RequiredFieldHelper{ public static void RenderBeginTag(IRequirableField field, HtmlTextWriter writer){ //check field.IsRequired, render based on its values } public static void RenderEndTag(IRequirableField field, HtmlTextWriter writer){ //check field.IsRequired , render based on its values } } If I was deriving all of my custom controls from the same base class, I could conceivably use Template Method to enforce the before/after behavior;but I have several base classes and I'd rather not end up with really a convoluted class hierarchy anyway. It feels like I should be able to design something more elegant (i.e. adheres to DRY and OCP) by leveraging the functional aspects of C#, but I'm drawing a blank.

  Read the article

• How can I implement a splay tree that performs the zig operation last, not first?

  - by Jakob

  For my Algorithms & Data Structures class, I've been tasked with implementing a splay tree in Haskell. My algorithm for the splay operation is as follows: If the node to be splayed is the root, the unaltered tree is returned. If the node to be splayed is one level from the root, a zig operation is performed and the resulting tree is returned. If the node to be splayed is two or more levels from the root, a zig-zig or zig-zag operation is performed on the result of splaying the subtree starting at that node, and the resulting tree is returned. This is valid according to my teacher. However, the Wikipedia description of a splay tree says the zig step "will be done only as the last step in a splay operation" whereas in my algorithm it is the first step in a splay operation. I want to implement a splay tree that performs the zig operation last instead of first, but I'm not sure how it would best be done. It seems to me that such an algorithm would become more complex, seeing as how one needs to find the node to be splayed before it can be determined whether a zig operation should be performed or not. How can I implement this in Haskell (or some other functional language)?

  Read the article

• Can you dynamically combine multiple conditional functions into one in Python?

  - by erich

  I'm curious if it's possible to take several conditional functions and create one function that checks them all (e.g. the way a generator takes a procedure for iterating through a series and creates an iterator). The basic usage case would be when you have a large number of conditional parameters (e.g. "max_a", "min_a", "max_b", "min_b", etc.), many of which could be blank. They would all be passed to this "function creating" function, which would then return one function that checked them all. Below is an example of a naive way of doing what I'm asking: def combining_function(max_a, min_a, max_b, min_b, ...): f_array = [] if max_a is not None: f_array.append( lambda x: x.a < max_a ) if min_a is not None: f_array.append( lambda x: x.a > min_a ) ... return lambda x: all( [ f(x) for f in f_array ] ) What I'm wondering is what is the most efficient to achieve what's being done above? It seems like executing a function call for every function in f_array would create a decent amount of overhead, but perhaps I'm engaging in premature/unnecessary optimization. Regardless, I'd be interested to see if anyone else has come across usage cases like this and how they proceeded. Also, if this isn't possible in Python, is it possible in other (perhaps more functional) languages?

  Read the article

• How can I write simulations in Erlang?

  - by rick

  Hi guys, I want to do some numerical stuff in Erlang like this: You've got an array with the following values: [2,3,4] In each iteration, you calculate 0.1 * [n-1] + 0.7 *[n] + 0.2 * [n+1] This becomes the new [n]. If n == 0 then [n-1] = 0. If [n] == length of array then [n] = 0. So I try an example: [2,3,4] calculations: 0.1 * 0 + 0.7 * 2 + 0.2 * 3 = 2 0.1 * 2 + 0.7 * 3 + 0.2 * 4 = 3.1 0.1 * 3 + 0.7 * 4 + 0.2 * 0 = 3.1 So [2,3,4] becomes to [2, 3.1, 3.1] after one iteration. I know how to write this in a non-functional language like C. But I have difficulties to imagine, how this could be done in Erlang. I found some tutorials on how you read a file to a list. So this is not the problem. How can I spawn different Erlang processes that each process has one element of the list? How can I do calculations by communicating with 'the neighbors', so that the neighbors know where their neigbors are generically, without specifying each? How can I collect the data into a list? Eventually, is it possible to solve that problem in Erlang at all? Thanks for your help.

  Read the article

• Assign a static function to a variable in PHP

  - by Felipe Almeida

  I would like to assign a static function to a variable so that I can send it around as a parameter. For example: class Foo{ private static function privateStaticFunction($arg1,$arg2){ //compute stuff on the args } public static function publicStaticFunction($foo,$bar){ //works $var = function(){ //do stuff }; //also works $var = function($someArg,$someArg2){ //do stuff }; //Fatal error: Undefined class constant 'privateStaticFunction' $var = self::privateStaticMethod; //same error $var = Foo::privateStaticFunction; //compiles, but errors when I try to run $var() somewhere else, as expected //Fatal error: Call to private method Foo::privateStaticMethod() from context '' $var = function(){ return Foo::privateStaticMethod(); }; } } I've tried a few more variations but none of them worked. I don't even expect this sort of functional hacking to work with PHP but hey, who knows? Is it possible to do that in PHP or will I need to come up with some hack using eval? P.S.: LawnGnome on ##php mentioned something about it being possible to do what I want using array('Foo','privateStaticMethod') but I didn't understand what he meant and I didn't press him further as he looked busy.

  Read the article

• What was your the most impressive technical programming achievement performed to impress a romantic

  - by DVK

  OK, so the archetypal human story is for a guy to go out and impress the girl with some wonderful achievement like slaying a dragon or building a monument or conquering neighboring tribe. This being enlightened 21st century on SO, let's morph this into a: StackOverflower performing a feat of programming to impress a romantic interest. There are two ways to do this: Technical achievement: Impressing a person with suitable background/understanding of programming with actual coding powerss you displayed. A dumb movie example would be that kid in "Hackers" move showing off his hacking skills in front of Angeline Jolie. Artistic achievement: Impressing a person with a result of running said code, whether they understand just how incredible the code itself is. An example is the animated ANSI rose (for a guy who actually wrote the ANSI code) This question is only about the first kind (technical achievements) - e.g. the person of interest was presented with impressive code/design that (s)he was able to properly appreciate. Rules (what doesn't qualify): The target audience must have been a person of romantic interest (prospective or present significant other or random hook-up). E.g. showing your program to your sister who's also a software developer doesn't count. The achievement must have been done specifically with the goal to impress such a person. However, it is OK if the achievement was done to impress a generic qualifying person, not someone specific. Although... if you write code to impress girls in general, I'd say "get a better idea of the opposite sex" The achievement must have been done with the goal of impressing the person. In other words, if you would have done it without romantic interest's knowledge anyway, it doesn't count. As examples, the following does not count: programming for your job. Programming for a coding contest. Open Source program that you'd have done anyway. The precise nature of the awesomeness of the achievement is somewhat irrelevant - from learning entire J2EE in 2 days to writing fancy game engine to implementing Python compiler in LOGO. As long as it's programming/software development related. The achievement should preferably be something other people would rank highly as well. If your date was impressed with your skill at calculating Fibonacci sequence without recursive function calls, it doesn't mean most developers will be. But it does mean you need to start finding better things to do on dates ;)

  Read the article

• Clojure: Testing every value from map operation for truth

  - by Ralph

  How can I test that every value in the collection returned by map is true? I am using the following: (defn test [f coll] (every? #(identity %) (map f coll))) with the anonymous function #(identity %), but I was wondering if there is a better way. I cannot use (apply and ...) because and is a macro. UPDATE: BTW, I am making my way through The Haskell Road to Logic, Maths, and Programming, by Kees Doets and Jan can Eijck, but doing the exercises in Clojure. It's a very interesting book.

  Read the article

< Previous Page | 71 72 73 74 75 76 77 78 79 80 81 82  | Next Page >