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  • Having a little trouble with this Java code. Beginner probably mixing some things with C#.

    - by Sergio Tapia
    package practico1; /** * Programador: Sergio Tapia Gutierrez * Fecha: Lunes 10, Mayo - 2010 * Practico: 1 */ public class Main { public static void main(String[] args) { System.out.println("Esta es una pequena aplicacion para mostrar los"); System.out.println("distintos tipos de datos que existen en Java 6."); //boolean, char, byte, short, int, long, float, double, String ejemplosBoolean(); } public void ejemplosBoolean(){ } } So, I'm just testing some things out, but I'm getting an error claiming that I'm trying to run ejemplosBoolean() in a static context when it isn't a static method. My question is, in Java do methods have to have static in order to use them even if they are in the same class?

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  • Can someone code review my small SDL app? Want to make sure I didn't make any beginner mistakes

    - by SDLFunTimes
    In an effort to teach myself the SDL library (hence my stack overflow handle :) ) I wanted to try my hand at a side-scroller. My code is complete but I want some feedback (mostly because I have an atrocious amount of if and else statements for what seems like some simple logic). My "program" is a c++ side-scroller where you move a single sprite across the screen. No jumping, bad guys, guns, scores, levels or anything. I wanted to use this as a base to build up upon. So I figured if my base is wrong I could end up with some pretty bad future apps. It's also multi-threaded. Next up on this I would like to make the person sprite animated (so it looks like he's walking rather than sliding) as well as make the person go faster when the arrow buttons are held down longer). The code is kind of long but here's my main method. There's a link at the bottom for the whole program: #include <iostream> #include "SDL.h" #include "game.hpp" using std::cout; using std::endl; const int SCREENW = 200; const int SCREENH = 200; const int BPP = 32; const int FPS = 24; int event_loop(void* stuff); int display_loop(void* stuff); int main(int argc, char** argv) { SDL_Init(SDL_INIT_EVERYTHING | SDL_INIT_EVENTTHREAD); SDL_Thread* events_thurd; SDL_Thread* display_thurd; SDL_Surface* screen = SDL_SetVideoMode(SCREENW, SCREENH, BPP, SDL_SWSURFACE); SDL_EnableKeyRepeat(SDL_DEFAULT_REPEAT_DELAY, SDL_DEFAULT_REPEAT_INTERVAL); SDL_Event event; Game* thug_aim = new Game(&event, screen, SCREENW, SCREENH, BPP); events_thurd = SDL_CreateThread(event_loop, (void*)thug_aim); display_thurd = SDL_CreateThread(display_loop, (void*)thug_aim); SDL_WaitThread(events_thurd, NULL); SDL_KillThread(display_thurd); delete thug_aim; return 0; } int event_loop(void* stuff) { Game* gamez = (Game*)stuff; SDL_Event* event = gamez->get_event(); while(1) { while(SDL_PollEvent(event)) { if(event->type == SDL_QUIT) { return 0; } else if(event->type == SDL_KEYDOWN) { if(event->key.keysym.sym == SDLK_LEFT || event->key.keysym.sym == SDLK_RIGHT) { gamez->move(event->key.keysym.sym); } } else if(event->type == SDL_KEYUP) { if(event->key.keysym.sym == SDLK_LEFT || event->key.keysym.sym == SDLK_RIGHT) { gamez->stop_move(event->key.keysym.sym); } } else { //not an event that concerns this game } } } } int display_loop(void* stuff) { Game* gamez = (Game*)stuff; double period = 1 / FPS * 1000; Uint32 milli_period = (Uint32)period; //get some of the attributes from gamez SDL_Rect* background_rect = gamez->get_background_rect(); SDL_Rect* person_rect = gamez->get_person_rect(); SDL_Surface* screen = gamez->get_screen(); SDL_Surface* background = gamez->get_background(); SDL_Surface* person = gamez->get_person(); Uint32 start, end; int sleep; while(1) { start = SDL_GetTicks(); //blit background SDL_BlitSurface(background, background_rect, screen, NULL); //blit person SDL_BlitSurface(person, NULL, screen, person_rect); end = SDL_GetTicks(); sleep = milli_period - (end - start); if(sleep < 0) { sleep = 0; } SDL_Delay((Uint32)sleep); if(SDL_Flip(gamez->get_screen()) != 0) { cout << "error drawing to screen: " << SDL_GetError() << endl; } } } Here's the link to the .zip file of all my code (please ignore some of the variable names ;-) ): Anyway can you guys take a look and tell me what you think? url edit: holy crap I didn't know 2shared was such a shitty site. Looking for a better uploader than that or rapidshare / mediafire.

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  • Beginner question: ArrayList can't seem to get it right! Pls help

    - by elementz
    I have been staring at this code all day now, but just can't get it right. ATM I am just pushing codeblocks around without being able to concentrate anymore, with the due time being within almost an hour... So you guys are my last resort here. I am supposed to create a few random balls on a canvas, those balls being stored within an ArrayList (I hope an ArrayList is suitable here: the alternative options to choose from were HashSet and HashMap). Now, whatever I do, I get the differently colored balls at the top of my canvas, but they just get stuck there and refuse to move at all. Apart from that I now get a ConcurrentModificationException, when running the code: java.util.ConcurrentModificationException at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372) at java.util.AbstractList$Itr.next(AbstractList.java:343) at BallDemo.bounce(BallDemo.java:109) Reading up on that exception, I found out that one can make sure ArrayList is accessed in a threadsafe manner by somehow synchronizing access. But since I have remember fellow students doing without synchronizing, my guess is, that it would actually be the wrong path to go. Maybe you guys could help me get this to work, I at least need those stupid balls to move ;-) /** * Simulate random bouncing balls */ public void bounce(int count) { int ground = 400; // position of the ground line System.out.println(count); myCanvas.setVisible(true); // draw the ground myCanvas.drawLine(50, ground, 550, ground); // Create an ArrayList of type BouncingBalls ArrayList<BouncingBall>balls = new ArrayList<BouncingBall>(); for (int i = 0; i < count; i++){ Random numGen = new Random(); // Creating a random color. Color col = new Color(numGen.nextInt(256), numGen.nextInt(256), numGen.nextInt(256)); // creating a random x-coordinate for the balls int ballXpos = numGen.nextInt(550); BouncingBall bBall = new BouncingBall(ballXpos, 80, 20, col, ground, myCanvas); // adding balls to the ArrayList balls.add(bBall); bBall.draw(); boolean finished = false; } for (BouncingBall bBall : balls){ bBall.move(); } } This would be the original unmodified method we got from our teacher, which only creates two balls: /** * Simulate two bouncing balls */ public void bounce() { int ground = 400; // position of the ground line myCanvas.setVisible(true); myCanvas.drawLine(50, ground, 550, ground); // draw the ground // crate and show the balls BouncingBall ball = new BouncingBall(50, 50, 16, Color.blue, ground, myCanvas); ball.draw(); BouncingBall ball2 = new BouncingBall(70, 80, 20, Color.red, ground, myCanvas); ball2.draw(); // make them bounce boolean finished = false; while(!finished) { myCanvas.wait(50); // small delay ball.move(); ball2.move(); // stop once ball has travelled a certain distance on x axis if(ball.getXPosition() >= 550 && ball2.getXPosition() >= 550) { finished = true; } } ball.erase(); ball2.erase(); } }

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  • Prolog Beginner: How to unify with arithmentic comparison operators or how to get a set var to range

    - by sixtyfootersdude
    I am new to prolog. I need to write an integer adder that will add numbers between 0-9 to other numbers 0-9 and produce a solution 0-18. This is what I want to do: % sudo code add(in1, in2, out) :- in1 < 10, in2 < 10, out < 18. I would like to be able to call it like this: To Check if it is a valid addition: ?- add(1,2,3). true ?- add(1,2,4). false With one missing variable: ?- add(X,2,3). 1 ?- add(1,4,X). 5 With multiple missing variables: ?-add(X,Y,Z). % Some output that would make sense. Some examples could be: X=1, Y=1, Z=2 ; X=2, Y=1, Z=3 ...... I realize that this is probably a pretty simplistic question and it is probably very straightforward. However cording to the prolog tutorial I am using: "Unlike unification Arithmetic Comparison Operators operators cannot be used to give values to a variable. The can only be evaluated when every term on each side have been instantiated."

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  • Java queue and multi-dimention array question? [Beginner level]

    - by javaLearner.java
    First of all, this is my code (just started learning java): Queue<String> qe = new LinkedList<String>(); qe.add("b"); qe.add("a"); qe.add("c"); qe.add("d"); qe.add("e"); My question: Is it possible to add element to the queue with two values, like: qe.add("a","1"); // where 1 is integer So, that I know element "a" have value 1. If I want to add a number let say "2" to element a, I will have like a = 3. If this cant be done, what else in java classes that can handle this? I tried to use multi-dimention array, but its kinda hard to do the queue, like pop, push etc. (Maybe I am wrong) How to call specific element in the queue? Like, call element a, to check its value. [Note] Please don't give me links that ask me to read java docs. I was reading, and I still dont get it. The reason why I ask here is because, I know I can find the answer faster and easier.

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  • Prolog Beginner: How to make unique values for each Variable in a predicate.

    - by sixtyfootersdude
    I have a prolog predicate: DoStuff( [A|B] ) :- <Stuff that I do> ... </Stuff that I do> It is all done except it needs to do return unique values. Ie if you do: ?- DoStuff(A,B,C,D). it should return: A=1; B=2; C=3; D=4. (Or something similar, the key point is that all of the values are unique). However you should be able to do this too: ?- DoStuff(A,A,B,B). And still get a valid answer. Ie: A=1; B=2. How can I do this? What I was planning on doing was something like this: DoStuff( [A|B] ) :- <Stuff that I do> ... </Stuff that I do> unique([A|B]). unique([]). unique([A|B]) :- A is not B. However I think that will make DoStuff([A,A,B]) not work because not all values will be unique.

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  • How do I make a project in Django? Beginner

    - by ggfan
    Okay I just started with Django and it's totally different from PHP. I installed Python 2.6 and Django. Both are located in my C drive. C: Django build django docs Python26 I am doing the django site tutorial and when they say to write django-admin.py startproject mysite from my Python command line, I keep getting: Syntax error: invalid syntax >>>django-admin.py startproject mysite FILE "<stdin>", line 1 django-admin.py startproject mysite ^ My django-admin.py is in the django/bin folder. I installed Python via python setup.py. Am I suppose to use my window's CP? When I do that, I get window's can't open a .py file. I thought I was just creating a folder? How do I create a project with django? Thanks :)

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  • C++ Beginner - Best way to read 3 consecutive values from the command line?

    - by Francisco P.
    Hello everyone, I am writing a text-based Scrabble implementation for a college project. The specification states that the user's position input must be read from single line, like this: Coordinates of the word's first letter and orientation (<A – P> <1 – 15> <H ou V>): G 5 H G 5 H is the user's input for that particular example. The order, as shown, must be char int char. What is the best way to read the user's input? cin >> row >> column >> orientation will cause crashes if the user screws up. A getline and a subsequent string parser are a valid solution, but represent a bit of work. Is there another, better, way to do this, that I am missing? Thanks for your time!

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  • Java Beginner Question : What is wrong with the code below ?

    - by happysoul
    public class Function { public static void main(String args[]) { System.out.println(power(3,2)); System.out.println(power(3,2)); System.out.println(power(2)); } public long power(int m) { return m*m; } public long power(int m,int n) { long product=1; for(int i=1;i<=n;i++) { product=product*m; } return product; } } Compiler displays this error :- Function.java:5: non-static method power(int,int) cannot be referenced from a static context

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  • Beginner MVC question - Correct approach to render out a List and details?

    - by fizzer
    I'm trying to set up a page where I display a list of items and the details of the selected item. I have it working but wonder whether I have followed the correct approach. I'll use customers as an example I have set the aspx page to inherit from an IEnumerable of Customers. This seems to be the standard approach to display the list of items. For the Details I have added a Customer user control which inherits from customer. I think i'm on the right track so far but I was a bit confused as to where I should store the id of the customer whose details I intend to display. I wanted to make the id optional in the controller action so that the page could be hit using "/customers" or "customers/1" so I made the arg optional and stored the id in the ViewData like this: public ActionResult Customers(string id = "0") { Models.DBContext db = new Models.DBContext(); var cList = db.Customers.OrderByDescending(c => c.CustomerNumber); if (id == "0") { ViewData["CustomerNumber"] = cList.First().CustomerNumber.ToString(); } else { ViewData["CustomerNumber"] = id; } return View("Customers", cList); } I then rendered the User control using RenderPartial in the front end: <%var CustomerList = from x in Model where x.CustomerNumber == Convert.ToInt32(ViewData["CustomerNumber"]) select x; Customer c = (Customer)CustomerList.First(); %> <% Html.RenderPartial("Customer",c); %> Then I just have an actionLink on each listed item: <%: Html.ActionLink("Select", "Customers", new { id = item.CustomerNumber })% It all seems to work but as MVC is new to me I would just be interested in others thoughts on whether this is a good approach?

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  • Prolog Beginner: How to unify with arithmentic cmparison operators or how to get a set var to range

    - by sixtyfootersdude
    I am new to prolog. I need to write an integer adder that will add numbers between 0-9 to other numbers 0-9 and produce a solution 0-18. This is what I want to do: add(in1, in2, out) :- in1 < 10, in2 < 10, out < 18. I would like to be able to call it like this: To Check if it is a valid addition: ?- add(1,2,3). true ?- add(1,2,4). false With one missing variable: ?- add(X,2,3). 1 ?- add(1,4,X). 5 With multiple missing variables: ?-add(X,Y,Z). % Some output that would make sense. Some examples could be: X=1, Y=1, Z=2 ; X=2, Y=1, Z=3 ...... I realize that this is probably a pretty simplistic question and it is probably very straightforward. However cording to the prolog tutorial I am using: "Unlike unification Arithmetic Comparison Operators operators cannot be used to give values to a variable. The can only be evaluated when every term on each side have been instantiated."

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  • Prolog Beginner: Trivial Example that I cannot get to work.

    - by sixtyfootersdude
    I have some prolog. The lessThanTen and example predicates work as expected however the exam predicate does not work. lessThanTen(9). lessThanTen(8). lessThanTen(7). lessThanTen(6). lessThanTen(5). lessThanTen(4). lessThanTen(3). lessThanTen(2). lessThanTen(1). lessThanTen(0). example(X) :- X is 5. exam(X) :- X is lessThanTen(Y). Here is the output: % swipl ... ?- [addv1]. Warning: /.../addv1.pl:17: Singleton variables: [Y] % addv1 compiled 0.00 sec, 1,484 bytes true. ?- lessThanTen(X). X = 9 ; X = 8 ; X = 7 ; ... ?- example(X). X = 5. ?- exam(X). ERROR: is/2: Arithmetic: `lessThanTen/1' is not a function ?- exam(5). ERROR: is/2: Arithmetic: `lessThanTen/1' is not a function I am thinking that the warning I am getting is pretty key.

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  • C++ Beginner - Simple block of code crashing, reason unknown.

    - by Francisco P.
    Hello everyone, Here's a block of code I'm having trouble with. string Game::tradeRandomPieces(Player & player) { string hand = player.getHand(); string piecesRemoved; size_t index; for (size_t numberOfPiecesToTrade = rand() % hand.size() + 1; numberOfPiecesToTrade != 0; --numberOfPiecesToTrade) { index = rand() % hand.size(); piecesRemoved += hand[index]; hand.erase(index,1); } player.removePiecesFromHand(piecesRemoved); player.fillHand(_deck); return piecesRemoved; } I believe the code is pretty self explanatory. fillhand and removepiecesfromhand are working fine, so that's not it. I really can't get what's wrong with this :( Thanks for your time

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  • Beginner: How to Find What Codecs You Need to Play Any Media File

    - by Taylor Gibb
    There must have been an occasion when you launched a video and got sound but no picture. The most likely cause is that you never had the correct codec installed, so here’s how to find out exactly which codec is needed to play any media file. How to Use an Xbox 360 Controller On Your Windows PC Download the Official How-To Geek Trivia App for Windows 8 How to Banish Duplicate Photos with VisiPic

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  • Dash brings up 2nd instance of an app

    - by John Rose
    When I select an app from the Launch panel, it returns to the app if already loaded (i.e. shows the app's window with the 'old' situation in it, such as the document last worked on by LibreOffice Writer). However, if I click on the app after clicking the Dash icon in the Launch panel, it always seems to bring up a new instance of the app. Is there a way to make the Dash return to the app as per direct selection of the app from the Launch panel.

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  • Mail.app send mail hook

    - by Charles Stewart
    Is there any way to run a script whenever the user tries to send mail? I'm particularly interested in ensuring that outbound mail doesn't have a blank subject line. Solutions that involve plug-ins are welcome!

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  • Changing Win 8.1 Pro Store App Installation Folder

    - by ChiliYago
    I have a Dell Venue 8 Pro tablet with Windows 8.1. The c:\ is very limited capacity at only 24GB. With the OS only on the c:\ I just have 8.6GB of free space. So I have added a 64gb SSD to the machine and want to install all my apps on it and not the C Drive. I know the apps get installed in c:\Program Files\WindowsApps folder so I have ROBOCOPY'd all the files to d:\Program Files\WindowsApps and created a symbolic link using mklink. It seems that new apps are install correctly now on d:\ however the existing apps fail to open. What is the Microsoft's solution to making this happen seamlessly?

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  • Weird behaviour/rendering of backspace in Terminal.app when SSHing into zsh

    - by Nils Riedemann
    Hi there, I just stumbled upon a weird problem. When I SSH into my server (centos, zsh) and I type some stuff and hit backspace It looks like a space - but internally it really deleted the characters. ls -l a Note that the space between land a is actually when I hit backspace. When I now hit return ls -a gets executed. This is only in zsh, in bash it works fine. Hope anyone has an idea what this is all about and how to fix this.

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  • Weird behaviour/rendering of backspace in Terminal.app when SSHing into zsh using tmux/screen

    - by Nils Riedemann
    Hi there, I just stumbled upon a weird problem. When I SSH into my server (centos, zsh) and I type some stuff and hit backspace It looks like a space - but internally it really deleted the characters. ls -l a Note that the space between land a is actually when I hit backspace. When I now hit return ls -a gets executed. This is only in zsh, in bash it works fine. Hope anyone has an idea what this is all about and how to fix this. Update: Only happens when using tmux/screen

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  • How does Google App Engine precompile Java ?

    - by Thilo
    App Engine uses a "precompilation" process with the Java bytecode of an app to enhance the performance of the app in the Java runtime environment. Precompiled code functions identically to the original bytecode. Is there any detailed information what this does?

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  • Why is this class library dll not getting information from app.config

    - by baron
    I am developing a custom HttpHandler, to do so I write a C# Class Library and compile to DLL. As part of this I have some directory locations which I want not hard coded in the app, so i'm trying to put it in the app.config which I've used before. Before this has worked by just going building the app.config: <?xml version="1.0" encoding="utf-8" ?> <configuration> <appSettings> <add key="Share" value="C:\...\"/> </appSettings> </configuration> And then obtaining this in code like: var shareDirectory = ConfigurationManager.AppSettings["Share"]; But when I compile it and put it in the bin folder for the webservice, it keeps getting null for shareDirectory, probably because it can't find app.config. So how do I make sure this is included so I don't have to hard code my direcotry locations? I notice it will essentially after compiled we get the assembly.dll and the assembly.dll.config which is the app.config file, so it's definetly there in the bin folder!

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