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  • Reproducing a Conversion Deadlock

    - by Alexander Kuznetsov
    Even if two processes compete on only one resource, they still can embrace in a deadlock. The following scripts reproduce such a scenario. In one tab, run this: CREATE TABLE dbo.Test ( i INT ) ; GO INSERT INTO dbo.Test ( i ) VALUES ( 1 ) ; GO SET TRANSACTION ISOLATION LEVEL SERIALIZABLE ; BEGIN TRAN SELECT i FROM dbo.Test ; --UPDATE dbo.Test SET i=2 ; After this script has completed, we have an outstanding transaction holding a shared lock. In another tab, let us have that another connection have...(read more)

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  • How to access values of dynamically created TextBoxes

    - by SAMIR BHOGAYTA
    If one adds controls dynamically to a page and wants to get their information after PostBack, one needs to recreate these elements after the PostBack. Let's consider the following idea: First you create some controls: for(int i=0;i TextBox objBox = new TextBox(); objBox.ID = "objBox" + i.ToString(); this.Page.Controls.Add(objBox); } After PostBack, you want to retrieve the text entered in the third TextBox. If you try this: String strText = objBox2.Text; you'll receive an exception. Why? Because the boxes have not been created again and the local variable objBox2 simply not exists. How to retrieve the Box? You'll need to recreate the box by using the code above. Then, you may try to get its value by using the following code: TextBox objBox2; objBox2 = this.Page.FindControl("objBox2") as TextBox; if(objBox2 != null) Response.Write(objBox2.Text);

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  • Which of these algorithms is best for my goal?

    - by JonathonG
    I have created a program that restricts the mouse to a certain region based on a black/white bitmap. The program is 100% functional as-is, but uses an inaccurate, albeit fast, algorithm for repositioning the mouse when it strays outside the area. Currently, when the mouse moves outside the area, basically what happens is this: A line is drawn between a pre-defined static point inside the region and the mouse's new position. The point where that line intersects the edge of the allowed area is found. The mouse is moved to that point. This works, but only works perfectly for a perfect circle with the pre-defined point set in the exact center. Unfortunately, this will never be the case. The application will be used with a variety of rectangles and irregular, amorphous shapes. On such shapes, the point where the line drawn intersects the edge will usually not be the closest point on the shape to the mouse. I need to create a new algorithm that finds the closest point to the mouse's new position on the edge of the allowed area. I have several ideas about this, but I am not sure of their validity, in that they may have far too much overhead. While I am not asking for code, it might help to know that I am using Objective C / Cocoa, developing for OS X, as I feel the language being used might affect the efficiency of potential methods. My ideas are: Using a bit of trigonometry to project lines would work, but that would require some kind of intense algorithm to test every point on every line until it found the edge of the region... That seems too resource intensive since there could be something like 200 lines that would have each have to have as many as 200 pixels checked for black/white.... Using something like an A* pathing algorithm to find the shortest path to a black pixel; however, A* seems resource intensive, even though I could probably restrict it to only checking roughly in one direction. It also seems like it will take more time and effort than I have available to spend on this small portion of the much larger project I am working on, correct me if I am wrong and it would not be a significant amount of code (100 lines or around there). Mapping the border of the region before the application begins running the event tap loop. I think I could accomplish this by using my current line-based algorithm to find an edge point and then initiating an algorithm that checks all 8 pixels around that pixel, finds the next border pixel in one direction, and continues to do this until it comes back to the starting pixel. I could then store that data in an array to be used for the entire duration of the program, and have the mouse re-positioning method check the array for the closest pixel on the border to the mouse target position. That last method would presumably execute it's initial border mapping fairly quickly. (It would only have to map between 2,000 and 8,000 pixels, which means 8,000 to 64,000 checked, and I could even permanently store the data to make launching faster.) However, I am uncertain as to how much overhead it would take to scan through that array for the shortest distance for every single mouse move event... I suppose there could be a shortcut to restrict the number of elements in the array that will be checked to a variable number starting with the intersecting point on the line (from my original algorithm), and raise/lower that number to experiment with the overhead/accuracy tradeoff. Please let me know if I am over thinking this and there is an easier way that will work just fine, or which of these methods would be able to execute something like 30 times per second to keep mouse movement smooth, or if you have a better/faster method. I've posted relevant parts of my code below for reference, and included an example of what the area might look like. (I check for color value against a loaded bitmap that is black/white.) // // This part of my code runs every single time the mouse moves. // CGPoint point = CGEventGetLocation(event); float tX = point.x; float tY = point.y; if( is_in_area(tX,tY, mouse_mask)){ // target is inside O.K. area, do nothing }else{ CGPoint target; //point inside restricted region: float iX = 600; // inside x float iY = 500; // inside y // delta to midpoint between iX,iY and tX,tY float dX; float dY; float accuracy = .5; //accuracy to loop until reached do { dX = (tX-iX)/2; dY = (tY-iY)/2; if(is_in_area((tX-dX),(tY-dY),mouse_mask)){ iX += dX; iY += dY; } else { tX -= dX; tY -= dY; } } while (abs(dX)>accuracy || abs(dY)>accuracy); target = CGPointMake(roundf(tX), roundf(tY)); CGDisplayMoveCursorToPoint(CGMainDisplayID(),target); } Here is "is_in_area(int x, int y)" : bool is_in_area(NSInteger x, NSInteger y, NSBitmapImageRep *mouse_mask){ NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init]; NSUInteger pixel[4]; [mouse_mask getPixel:pixel atX:x y:y]; if(pixel[0]!= 0){ [pool release]; return false; } [pool release]; return true; }

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  • GameplayScreen does not contain a definition for GraphicsDevice

    - by Dave Voyles
    Long story short: I'm trying to intergrate my game with Microsoft's Game State Management. In doing so I've run into some errors, and the latest one is in the title. I'm not able to display my HUD for the reasons listed above. Previously, I had much of my code in my Game.cs class, but the GSM has a bit of it in Game1, and most of what you have drawn for the main screen in your GameplayScreen class, and that is what is causing confusion on my part. I've created an instance of the GameplayScreen class to be used in the HUD class (as you can see below). Before integrating with the GSM however, I created an instance of my Game class, and all worked fine. It seems that I need to define my graphics device somewhere, but I am not sure of where exactly. I've left some code below to help you understand. public class GameStateManagementGame : Microsoft.Xna.Framework.Game { #region Fields GraphicsDeviceManager graphics; ScreenManager screenManager; // Creates a new intance, which is used in the HUD class public static Game Instance; // By preloading any assets used by UI rendering, we avoid framerate glitches // when they suddenly need to be loaded in the middle of a menu transition. static readonly string[] preloadAssets = { "gradient", }; #endregion #region Initialization /// <summary> /// The main game constructor. /// </summary> public GameStateManagementGame() { Content.RootDirectory = "Content"; graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = 1280; graphics.PreferredBackBufferHeight = 720; graphics.IsFullScreen = false; graphics.ApplyChanges(); // Create the screen manager component. screenManager = new ScreenManager(this); Components.Add(screenManager); // Activate the first screens. screenManager.AddScreen(new BackgroundScreen(), null); //screenManager.AddScreen(new MainMenuScreen(), null); screenManager.AddScreen(new PressStartScreen(), null); } namespace Pong { public class HUD { public void Update(GameTime gameTime) { // Used in the Draw method titleSafeRectangle = new Rectangle (GameplayScreen.Instance.GraphicsDevice.Viewport.TitleSafeArea.X, GameplayScreen.Instance.GraphicsDevice.Viewport.TitleSafeArea.Y, GameplayScreen.Instance.GraphicsDevice.Viewport.TitleSafeArea.Width, GameplayScreen.Instance.GraphicsDevice.Viewport.TitleSafeArea.Height); } } } class GameplayScreen : GameScreen { #region Fields ContentManager content; public static GameStates gamestate; private GraphicsDeviceManager graphics; public int screenWidth; public int screenHeight; private Texture2D backgroundTexture; private SpriteBatch spriteBatch; private Menu menu; private SpriteFont arial; private HUD hud; Animation player; // Creates a new intance, which is used in the HUD class public static GameplayScreen Instance; public GameplayScreen() { TransitionOnTime = TimeSpan.FromSeconds(1.5); TransitionOffTime = TimeSpan.FromSeconds(0.5); } protected void Initialize() { lastScored = false; menu = new Menu(); resetTimer = 0; resetTimerInUse = true; ball = new Ball(content, new Vector2(screenWidth, screenHeight)); SetUpMulti(); input = new Input(); hud = new HUD(); // Places the powerup animation inside of the surrounding box // Needs to be cleaned up, instead of using hard pixel values player = new Animation(content.Load<Texture2D>(@"gfx/powerupSpriteSheet"), new Vector2(103, 44), 64, 64, 4, 5); // Used by for the Powerups random = new Random(); vec = new Vector2(100, 50); vec2 = new Vector2(100, 100); promptVec = new Vector2(50, 25); timer = 10000.0f; // Starting value for the cooldown for the powerup timer timerVector = new Vector2(10, 10); //JEP - one time creation of powerup objects playerOnePowerup = new Powerup(); playerOnePowerup.Activated += PowerupActivated; playerOnePowerup.Deactivated += PowerupDeactivated; playerTwoPowerup = new Powerup(); playerTwoPowerup.Activated += PowerupActivated; playerTwoPowerup.Deactivated += PowerupDeactivated; //JEP - moved from events since these only need set once activatedVec = new Vector2(100, 125); deactivatedVec = new Vector2(100, 150); powerupReady = false; }

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  • Dans Guardian install

    - by Matt
    I'm trying to install Dans Guardian on a virtual machine. The instructions ask me to run the ./configure script and then execute the command make install. The configure script runs fine but the make install throws errors. Making all in src make[2]: Entering directory `/webmin/dansguardian-2.10/src' g++ -DHAVE_CONFIG_H -I. -I.. -D__CONFFILE='"/usr/local/etc/dansguardian/dansguardian.conf"' -D__LOGLOCATION='"/usr/local/var/log/dansguardian/"' -D__PIDDIR='"/usr/local/var/run"' -D__PROXYUSER='"nobody"' -D__PROXYGROUP='"nobody"' -D__CONFDIR='"/usr/local/etc/dansguardian"' -g -O2 -MT dansguardian-fancy.o -MD -MP -MF .deps/dansguardian-fancy.Tpo -c -o dansguardian-fancy.o `test -f 'downloadmanagers/fancy.cpp' || echo './'`downloadmanagers/fancy.cpp downloadmanagers/fancy.cpp: In member function âstd::string fancydm::timestring(int)â: downloadmanagers/fancy.cpp:507:72: error: âsnprintfâ was not declared in this scope make[2]: *** [dansguardian-fancy.o] Error 1 make[2]: Leaving directory `/webmin/dansguardian-2.10/src' make[1]: *** [all-recursive] Error 1 make[1]: Leaving directory `/webmin/dansguardian-2.10' make: *** [all] Error 2 I'm running 12.04 LTS server x64

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  • Actionscript 3.0 - Enemies do not move right in my platformer game

    - by Christian Basar
    I am making a side-scrolling platformer game in Flash (Actionscript 3.0). I have made lots of progress lately, but I have come across a new problem. I will give some background first. My game level's terrain (or 'floor') is referenced by a MovieClip variable called 'floor.' My desire is to have the Player and enemy characters walk along the terrain. I have gotten the Player character to move on the terrain just fine; he walks up/down hills and falls whenever there is no ground beneath him. Here is the code I created to allow the Player to follow the terrain correctly. Much more code is used to control the Player, but only this code deals with the Player character's following of the terrain and gravity. // If the Player's not on the ground (not touching the 'floor' MovieClip)... if (!onGround) { // Disable ducking downKeyPressed = false; // Increase the Player's 'y' position by his 'y' velocity player.y += playerYVel; } // Increase the 'playerYVel' variable so that the Player will fall // progressively faster down the screen. This code technically // runs "all the time" but in reality it only affects the player // when he's off the ground. playerYVel += gravity; // Give the Player a terminal velocity of 15 px/frame if (playerYVel > 15) { playerYVel = 15; } // If the Player has not hit the 'floor,' increase his falling //speed if (! floor.hitTestPoint(player.x, player.y, true)) { player.y += playerYVel; // The Player is not on the ground when he's not touching it onGround = false; } Since getting this code to work for the Player, I have created a 'SkullDemon' class, which is one of the planned enemies for my game. I want the 'SkullDemon' objects to move along the terrain like the Player does. With lots of great help, I have already coded the EventListeners, etc. necessary for the 'SkullDemons' to move. Unfortunately, I am having trouble getting them to move along the terrain. In fact, they do not touch the terrain at all; they move along the top of the boundary of the 'floor' MovieClip! I had a simple text diagram showing what I mean, but unfortunately Stackoverflow does not format it correctly. I hope my problem is clear from my description. Strangely enough, my code for the Player's movement and the 'SkullDemon's' movement is almost exactly the same, yet the 'SkullDemons' do not move like the Player does. Here is my code for the SkullDemon movement: // Move all of the Skull Demons using this method protected function moveSkullDemons():void { // Go through the whole 'skullDemonContainer' for (var skullDi:int = 0; skullDi < skullDemonContainer.numChildren; skullDi++) { // Set the SkullDemon 'instance' variable to equal the current SkullDemon skullDIns = SkullDemon(skullDemonContainer.getChildAt(skullDi)); // For now, just move the Skull Demons left at 5 units per second skullDIns.x -= 5; // If the Skull Demon has not hit the 'floor,' increase his falling //speed if (! floor.hitTestPoint(skullDIns.x, skullDIns.y, true)) { // Increase the Skull Demon's 'y' position by his 'y' velocity skullDIns.y += skullDIns.sdYVel; // The Skull Demon is not on the ground when he's not touching it skullDIns.sdOnGround = false; } // Increase the 'sdYVel' variable so that the Skull Demon will fall // progressively faster down the screen. This code technically // runs "all the time" but in reality it only affects the Skull Demon // when he's off the ground. if (! skullDIns.sdOnGround) { skullDIns.sdYVel += skullDIns.sdGravity; // Give the Skull Demon a terminal velocity of 15 px/frame if (skullDIns.sdYVel > 15) { skullDIns.sdYVel = 15; } } // What happens when the Skull Demon lands on the ground after a fall? // The Skull Demon is only on the ground ('onGround == true') when // the ground is touching the Skull Demon MovieClip's origin point, // which is at the Skull Demon's bottom centre for (var i:int = 0; i < 10; i++) { // The Skull Demon is only on the ground ('onGround == true') when // the ground is touching the Skull Demon MovieClip's origin point, // which is at the Skull Demon's bottom centre if (floor.hitTestPoint(skullDIns.x, skullDIns.y, true)) { skullDIns.y = skullDIns.y; // Set the Skull Demon's y-axis speed to 0 skullDIns.sdYVel = 0; // The Skull Demon is on the ground again skullDIns.sdOnGround = true; } } } } // End of 'moveSkullDemons()' function It is almost like the 'SkullDemons' are interacting with the 'floor' MovieClip using the hitTestObject() function, and not the hitTestPoint() function which is what I want, and which works for the Player character. I am confused about this problem and would appreciate any help you could give me. Thanks!

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  • Didn't do too well on a Java IKM test, advice?

    - by Jason
    I did an IKM Java test recently and got quite a low score. I only graduated a year ago and I dont have commercial experience in Java (i do web development in my current job). I thought reading up a lot on Java would help me prepare, but when I sat the IKM test i got ripped to pieces. I didn't know much about how the garbage collection actually works, names of other java compilers (i know about javac?), using .dll with Java etc etc. I know a wide range of the basics, but to the extent wether 'int(5L)' produces an integer or not, I really didnt know. My question is that many of the IKM questions I have never come across, yet I have read many of the wider-known Java programming books (Deitel, O'Reilly etc). Am i reading the wrong books??? Could anyone recommend a good plan of action to allow me to go away and self-study and be able to know these really tough java questions?

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  • C code - ls system command not showing bash colors

    - by m0atz
    I've just been fooling around with some code in C, an example of a really basic program is as follows which just, obviously, lists the directories using the ls system command. #include <stdio.h> int main (void) { system("ls -l -d */"); printf("I've just listed the directories :-)\n"); return 0; } This runs fine, but it shows the ls output in monochrome, whereas Bash would output the list using colors for the directories (or files if I included files). How can I make my C code use the bash colors? Thanks

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  • What if we run out of stack space in C# or Python?

    - by dotneteer
    Supposing we are running a recursive algorithm on a very large data set that requires, say, 1 million recursive calls. Normally, one would solve such a large problem by converting recursion to a loop and a stack, but what if we do not want to or cannot rewrite the algorithm? Python has the sys.setrecursionlimit(int) method to set the number of recursions. However, this is only part of the story; the program can still run our of stack space. C# does not have a equivalent method. Fortunately, both C# and Python have option to set the stack space when creating a thread. In C#, there is an overloaded constructor for the Thread class that accepts a parameter for the stack size: Thread t = new Thread(work, stackSize); In Python, we can set the stack size by calling: threading.stack_size(67108864) We can then run our work under a new thread with increased stack size.

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  • Solaris 11.2: Functional Deprecation

    - by alanc
    In Solaris 11.1, I updated the system headers to enable use of several attributes on functions, including noreturn and printf format, to give compilers and static analyzers more information about how they are used to give better warnings when building code. In Solaris 11.2, I've gone back in and added one more attribute to a number of functions in the system headers: __attribute__((__deprecated__)). This is used to warn people building software that they’re using function calls we recommend no longer be used. While in many cases the Solaris Binary Compatibility Guarantee means we won't ever remove these functions from the system libraries, we still want to discourage their use. I made passes through both the POSIX and C standards, and some of the Solaris architecture review cases to come up with an initial list which the Solaris architecture review committee accepted to start with. This set is by no means a complete list of Obsolete function interfaces, but should be a reasonable start at functions that are well documented as deprecated and seem useful to warn developers away from. More functions may be flagged in the future as they get deprecated, or if further passes are made through our existing deprecated functions to flag more of them. Header Interface Deprecated by Alternative Documented in <door.h> door_cred(3C) PSARC/2002/188 door_ucred(3C) door_cred(3C) <kvm.h> kvm_read(3KVM), kvm_write(3KVM) PSARC/1995/186 Functions on kvm_kread(3KVM) man page kvm_read(3KVM) <stdio.h> gets(3C) ISO C99 TC3 (Removed in ISO C11), POSIX:2008/XPG7/Unix08 fgets(3C) gets(3C) man page, and just about every gets(3C) reference online from the past 25 years, since the Morris worm proved bad things happen when it’s used. <unistd.h> vfork(2) PSARC/2004/760, POSIX:2001/XPG6/Unix03 (Removed in POSIX:2008/XPG7/Unix08) posix_spawn(3C) vfork(2) man page. <utmp.h> All functions from getutent(3C) man page PSARC/1999/103 utmpx functions from getutentx(3C) man page getutent(3C) man page <varargs.h> varargs.h version of va_list typedef ANSI/ISO C89 standard <stdarg.h> varargs(3EXT) <volmgt.h> All functions PSARC/2005/672 hal(5) API volmgt_check(3VOLMGT), etc. <sys/nvpair.h> nvlist_add_boolean(3NVPAIR), nvlist_lookup_boolean(3NVPAIR) PSARC/2003/587 nvlist_add_boolean_value, nvlist_lookup_boolean_value nvlist_add_boolean(3NVPAIR) & (9F), nvlist_lookup_boolean(3NVPAIR) & (9F). <sys/processor.h> gethomelgroup(3C) PSARC/2003/034 lgrp_home(3LGRP) gethomelgroup(3C) <sys/stat_impl.h> _fxstat, _xstat, _lxstat, _xmknod PSARC/2009/657 stat(2) old functions are undocumented remains of SVR3/COFF compatibility support If the above table is cut off when viewing in the blog, try viewing this standalone copy of the table. To See or Not To See To see these warnings, you will need to be building with either gcc (versions 3.4, 4.5, 4.7, & 4.8 are available in the 11.2 package repo), or with Oracle Solaris Studio 12.4 or later (which like Solaris 11.2, is currently in beta testing). For instance, take this oversimplified (and obviously buggy) implementation of the cat command: #include <stdio.h> int main(int argc, char **argv) { char buf[80]; while (gets(buf) != NULL) puts(buf); return 0; } Compiling it with the Studio 12.4 beta compiler will produce warnings such as: % cc -V cc: Sun C 5.13 SunOS_i386 Beta 2014/03/11 % cc gets_test.c "gets_test.c", line 6: warning: "gets" is deprecated, declared in : "/usr/include/iso/stdio_iso.h", line 221 The exact warning given varies by compilers, and the compilers also have a variety of flags to either raise the warnings to errors, or silence them. Of couse, the exact form of the output is Not An Interface that can be relied on for automated parsing, just shown for example. gets(3C) is actually a special case — as noted above, it is no longer part of the C Standard Library in the C11 standard, so when compiling in C11 mode (i.e. when __STDC_VERSION__ >= 201112L), the <stdio.h> header will not provide a prototype for it, causing the compiler to complain it is unknown: % gcc -std=c11 gets_test.c gets_test.c: In function ‘main’: gets_test.c:6:5: warning: implicit declaration of function ‘gets’ [-Wimplicit-function-declaration] while (gets(buf) != NULL) ^ The gets(3C) function of course is still in libc, so if you ignore the error or provide your own prototype, you can still build code that calls it, you just have to acknowledge you’re taking on the risk of doing so yourself. Solaris Studio 12.4 Beta % cc gets_test.c "gets_test.c", line 6: warning: "gets" is deprecated, declared in : "/usr/include/iso/stdio_iso.h", line 221 % cc -errwarn=E_DEPRECATED_ATT gets_test.c "gets_test.c", line 6: "gets" is deprecated, declared in : "/usr/include/iso/stdio_iso.h", line 221 cc: acomp failed for gets_test.c This warning is silenced in the 12.4 beta by cc -erroff=E_DEPRECATED_ATT No warning is currently issued by Studio 12.3 & earler releases. gcc 3.4.3 % /usr/sfw/bin/gcc gets_test.c gets_test.c: In function `main': gets_test.c:6: warning: `gets' is deprecated (declared at /usr/include/iso/stdio_iso.h:221) Warning is completely silenced with gcc -Wno-deprecated-declarations gcc 4.7.3 % /usr/gcc/4.7/bin/gcc gets_test.c gets_test.c: In function ‘main’: gets_test.c:6:5: warning: ‘gets’ is deprecated (declared at /usr/include/iso/stdio_iso.h:221) [-Wdeprecated-declarations] % /usr/gcc/4.7/bin/gcc -Werror=deprecated-declarations gets_test.c gets_test.c: In function ‘main’: gets_test.c:6:5: error: ‘gets’ is deprecated (declared at /usr/include/iso/stdio_iso.h:221) [-Werror=deprecated-declarations] cc1: some warnings being treated as errors Warning is completely silenced with gcc -Wno-deprecated-declarations gcc 4.8.2 % /usr/bin/gcc gets_test.c gets_test.c: In function ‘main’: gets_test.c:6:5: warning: ‘gets’ is deprecated (declared at /usr/include/iso/stdio_iso.h:221) [-Wdeprecated-declarations] while (gets(buf) != NULL) ^ % /usr/bin/gcc -Werror=deprecated-declarations gets_test.c gets_test.c: In function ‘main’: gets_test.c:6:5: error: ‘gets’ is deprecated (declared at /usr/include/iso/stdio_iso.h:221) [-Werror=deprecated-declarations] while (gets(buf) != NULL) ^ cc1: some warnings being treated as errors Warning is completely silenced with gcc -Wno-deprecated-declarations

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  • Project Euler 20: (Iron)Python

    - by Ben Griswold
    In my attempt to learn (Iron)Python out in the open, here’s my solution for Project Euler Problem 20.  As always, any feedback is welcome. # Euler 20 # http://projecteuler.net/index.php?section=problems&id=20 # n! means n x (n - 1) x ... x 3 x 2 x 1 # Find the sum of digits in 100! import time start = time.time() def factorial(n): if n == 0: return 1 else: return n * factorial(n-1) print sum([int(i) for i in str(factorial(100))]) print "Elapsed Time:", (time.time() - start) * 1000, "millisecs" a=raw_input('Press return to continue')

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  • [News] Le mouvement NoSQL et MongoDB

    Le mouvement "NoSQL" est une communaut? cr??e dans le but de promouvoir les bases de donn?es non relationnelles (d'o? le terme NoSQL). Dans cet hymne ? ce mouvement, Michael Kennedy, instructeur pour DevelopMentor, d?crit les pr?ceptes de NoSQL en l'illustrant ? travers un moteur finalement peu connu du grand public, MongoDB. A lire, tr?s int?ressant m?me si on ne partage pas l'opinion de cette communaut? : "(...) A basic SQL Server cluster might run you $100,000 just to get it up and running on decent hardware. Rather than leveraging crazy scaling-up options, the NoSQL databases let you scale-out. They make this possible (dare I say easy?) by dropping the relational aspects of a database (...) "

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  • Why does Clang/LLVM warn me about using default in a switch statement where all enumerated cases are covered?

    - by Thomas Catterall
    Consider the following enum and switch statement: typedef enum { MaskValueUno, MaskValueDos } testingMask; void myFunction(testingMask theMask) { switch theMask { case MaskValueUno: {}// deal with it case MaskValueDos: {}// deal with it default: {} //deal with an unexpected or uninitialized value } }; I'm an Objective-C programmer, but I've written this in pure C for a wider audience. Clang/LLVM 4.1 with -Weverything warns me at the default line: Default label in switch which covers all enumeration values Now, I can sort of see why this is there: in a perfect world, the only values entering in the argument theMask would be in the enum, so no default is necessary. But what if some hack comes along and throws an uninitialized int into my beautiful function? My function will be provided as a drop in library, and I have no control over what could go in there. Using default is a very neat way of handling this. Why do the LLVM gods deem this behaviour unworthy of their infernal device? Should I be preceding this by an if statement to check the argument?

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  • Not getting desired results with SSAO implementation

    - by user1294203
    After having implemented deferred rendering, I tried my luck with a SSAO implementation using this Tutorial. Unfortunately, I'm not getting anything that looks like SSAO, you can see my result below. You can see there is some weird pattern forming and there is no occlusion shading where there needs to be (i.e. in between the objects and on the ground). The shaders I implemented follow: #VS #version 330 core uniform mat4 invProjMatrix; layout(location = 0) in vec3 in_Position; layout(location = 2) in vec2 in_TexCoord; noperspective out vec2 pass_TexCoord; smooth out vec3 viewRay; void main(void){ pass_TexCoord = in_TexCoord; viewRay = (invProjMatrix * vec4(in_Position, 1.0)).xyz; gl_Position = vec4(in_Position, 1.0); } #FS #version 330 core uniform sampler2D DepthMap; uniform sampler2D NormalMap; uniform sampler2D noise; uniform vec2 projAB; uniform ivec3 noiseScale_kernelSize; uniform vec3 kernel[16]; uniform float RADIUS; uniform mat4 projectionMatrix; noperspective in vec2 pass_TexCoord; smooth in vec3 viewRay; layout(location = 0) out float out_AO; vec3 CalcPosition(void){ float depth = texture(DepthMap, pass_TexCoord).r; float linearDepth = projAB.y / (depth - projAB.x); vec3 ray = normalize(viewRay); ray = ray / ray.z; return linearDepth * ray; } mat3 CalcRMatrix(vec3 normal, vec2 texcoord){ ivec2 noiseScale = noiseScale_kernelSize.xy; vec3 rvec = texture(noise, texcoord * noiseScale).xyz; vec3 tangent = normalize(rvec - normal * dot(rvec, normal)); vec3 bitangent = cross(normal, tangent); return mat3(tangent, bitangent, normal); } void main(void){ vec2 TexCoord = pass_TexCoord; vec3 Position = CalcPosition(); vec3 Normal = normalize(texture(NormalMap, TexCoord).xyz); mat3 RotationMatrix = CalcRMatrix(Normal, TexCoord); int kernelSize = noiseScale_kernelSize.z; float occlusion = 0.0; for(int i = 0; i < kernelSize; i++){ // Get sample position vec3 sample = RotationMatrix * kernel[i]; sample = sample * RADIUS + Position; // Project and bias sample position to get its texture coordinates vec4 offset = projectionMatrix * vec4(sample, 1.0); offset.xy /= offset.w; offset.xy = offset.xy * 0.5 + 0.5; // Get sample depth float sample_depth = texture(DepthMap, offset.xy).r; float linearDepth = projAB.y / (sample_depth - projAB.x); if(abs(Position.z - linearDepth ) < RADIUS){ occlusion += (linearDepth <= sample.z) ? 1.0 : 0.0; } } out_AO = 1.0 - (occlusion / kernelSize); } I draw a full screen quad and pass Depth and Normal textures. Normals are in RGBA16F with the alpha channel reserved for the AO factor in the blur pass. I store depth in a non linear Depth buffer (32F) and recover the linear depth using: float linearDepth = projAB.y / (depth - projAB.x); where projAB.y is calculated as: and projAB.x as: These are derived from the glm::perspective(gluperspective) matrix. z_n and z_f are the near and far clip distance. As described in the link I posted on the top, the method creates samples in a hemisphere with higher distribution close to the center. It then uses random vectors from a texture to rotate the hemisphere randomly around the Z direction and finally orients it along the normal at the given pixel. Since the result is noisy, a blur pass follows the SSAO pass. Anyway, my position reconstruction doesn't seem to be wrong since I also tried doing the same but with the position passed from a texture instead of being reconstructed. I also tried playing with the Radius, noise texture size and number of samples and with different kinds of texture formats, with no luck. For some reason when changing the Radius, nothing changes. Does anyone have any suggestions? What could be going wrong?

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  • Is there a phrase or word to describe an algorithim or programme is complete in that given any value for its arguments there is a predictable outcome?

    - by Mrk Mnl
    Is there a phrase to describe an algorithim or programme is complete in that given any possible value for its arguments there is a predicatable outcome? i.e. all the ramifications have been considered whatever the context? A simple example would be the below function: function returns string get_item_type(int type_no) { if(type_no < 10) return "hockey stick" else if (type_no < 20) return "bulldozer" else return "unknown" } (excuse the dismal pseudo code) No matter what number is supplied all possibiblites are catered for. My question is: is there a word to fill the blank here: "get_item_type() is ______ complete" ? (The answer is not Turing Complete - that is something quite different - but I annoyingly always think of something as "Turing Complete" when I am thinking of the above).

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  • Android Loading Screen: How do I use a stack to load elements?

    - by tom_mai78101
    I have some problems with figuring out what value I should put in the function: int value_needed_to_figure_out = X; ProgressBar.incrementProgressBy(value_needed_to_figure_out); I've been researching about loading screens and how to use them. Some examples I've seen have implemented Thread.sleep() in a Handler.post(new Runnable()) function. To me, I got most of that concept of using the Handler to update the ProgressBar, while pretending to do some heavy crunching work. So, I kept looking. I have read this thread here: How do I load chunks of data from an assest manager during a loading screen? It said that I can try using a stack it needs to load, and adding a size counter as I add elements to the stack. What does it mean? This is the part where I'm totally stumped. If anyone would provide some hints, I'll gladly appreciate it. Thanks in advance.

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  • ReSharper 5.0s LINQ Refactoring Continues to be Amazing!

      In this post, well take a straight forward procedure based set of code and convert it to LINQ using a ReSharper from JetBrains suggestion.   The initial code is as follows: int... This site is a resource for asp.net web programming. It has examples by Peter Kellner of techniques for high performance programming...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • C#/.NET Little Wonders: Getting Caller Information

    - by James Michael Hare
    Originally posted on: http://geekswithblogs.net/BlackRabbitCoder/archive/2013/07/25/c.net-little-wonders-getting-caller-information.aspx Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. There are times when it is desirable to know who called the method or property you are currently executing.  Some applications of this could include logging libraries, or possibly even something more advanced that may server up different objects depending on who called the method. In the past, we mostly relied on the System.Diagnostics namespace and its classes such as StackTrace and StackFrame to see who our caller was, but now in C# 5, we can also get much of this data at compile-time. Determining the caller using the stack One of the ways of doing this is to examine the call stack.  The classes that allow you to examine the call stack have been around for a long time and can give you a very deep view of the calling chain all the way back to the beginning for the thread that has called you. You can get caller information by either instantiating the StackTrace class (which will give you the complete stack trace, much like you see when an exception is generated), or by using StackFrame which gets a single frame of the stack trace.  Both involve examining the call stack, which is a non-trivial task, so care should be done not to do this in a performance-intensive situation. For our simple example let's say we are going to recreate the wheel and construct our own logging framework.  Perhaps we wish to create a simple method Log which will log the string-ified form of an object and some information about the caller.  We could easily do this as follows: 1: static void Log(object message) 2: { 3: // frame 1, true for source info 4: StackFrame frame = new StackFrame(1, true); 5: var method = frame.GetMethod(); 6: var fileName = frame.GetFileName(); 7: var lineNumber = frame.GetFileLineNumber(); 8: 9: // we'll just use a simple Console write for now 10: Console.WriteLine("{0}({1}):{2} - {3}", 11: fileName, lineNumber, method.Name, message); 12: } So, what we are doing here is grabbing the 2nd stack frame (the 1st is our current method) using a 2nd argument of true to specify we want source information (if available) and then taking the information from the frame.  This works fine, and if we tested it out by calling from a file such as this: 1: // File c:\projects\test\CallerInfo\CallerInfo.cs 2:  3: public class CallerInfo 4: { 5: Log("Hello Logger!"); 6: } We'd see this: 1: c:\projects\test\CallerInfo\CallerInfo.cs(5):Main - Hello Logger! This works well, and in fact CallStack and StackFrame are still the best ways to examine deeper into the call stack.  But if you only want to get information on the caller of your method, there is another option… Determining the caller at compile-time In C# 5 (.NET 4.5) they added some attributes that can be supplied to optional parameters on a method to receive caller information.  These attributes can only be applied to methods with optional parameters with explicit defaults.  Then, as the compiler determines who is calling your method with these attributes, it will fill in the values at compile-time. These are the currently supported attributes available in the  System.Runtime.CompilerServices namespace": CallerFilePathAttribute – The path and name of the file that is calling your method. CallerLineNumberAttribute – The line number in the file where your method is being called. CallerMemberName – The member that is calling your method. So let’s take a look at how our Log method would look using these attributes instead: 1: static int Log(object message, 2: [CallerMemberName] string memberName = "", 3: [CallerFilePath] string fileName = "", 4: [CallerLineNumber] int lineNumber = 0) 5: { 6: // we'll just use a simple Console write for now 7: Console.WriteLine("{0}({1}):{2} - {3}", 8: fileName, lineNumber, memberName, message); 9: } Again, calling this from our sample Main would give us the same result: 1: c:\projects\test\CallerInfo\CallerInfo.cs(5):Main - Hello Logger! However, though this seems the same, there are a few key differences. First of all, there are only 3 supported attributes (at this time) that give you the file path, line number, and calling member.  Thus, it does not give you as rich of detail as a StackFrame (which can give you the calling type as well and deeper frames, for example).  Also, these are supported through optional parameters, which means we could call our new Log method like this: 1: // They're defaults, why not fill 'em in 2: Log("My message.", "Some member", "Some file", -13); In addition, since these attributes require optional parameters, they cannot be used in properties, only in methods. These caveats aside, they do let you get similar information inside of methods at a much greater speed!  How much greater?  Well lets crank through 1,000,000 iterations of each.  instead of logging to console, I’ll return the formatted string length of each.  Doing this, we get: 1: Time for 1,000,000 iterations with StackTrace: 5096 ms 2: Time for 1,000,000 iterations with Attributes: 196 ms So you see, using the attributes is much, much faster!  Nearly 25x faster in fact.  Summary There are a few ways to get caller information for a method.  The StackFrame allows you to get a comprehensive set of information spanning the whole call stack, but at a heavier cost.  On the other hand, the attributes allow you to quickly get at caller information baked in at compile-time, but to do so you need to create optional parameters in your methods to support it. Technorati Tags: Little Wonders,CSharp,C#,.NET,StackFrame,CallStack,CallerFilePathAttribute,CallerLineNumberAttribute,CallerMemberName

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  • [News] La communaut? ALT.NET est-elle sur le d?clin ?

    La communaut? ALT.NET s'est ?rig? comme symbole d'une bataille contre le d?veloppement ? quick and dirty ? pr?n? ? l??poque par Microsoft (Dataset, applications monolithiques, ?). S?appuyant sur les concepts de l'agilit? (tests unitaires, le mapping O/R, DDD et n-tiers), le mouvement a eu un ?cho important au d?but et semble un peu s'essouffler sur la dur?e. Dans ce billet, Ian Cooper entame une r?flexion de fond sur l'int?r?t et l'utilit? de cette communaut?. D'autant plus que Microsoft a depuis largement fait le m?nage dans sa culture.

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  • Having a generic data type for a database table column, is it "good" practice?

    - by Yanick Rochon
    I'm working on a PHP project where some object (class member) may contain different data type. For example : class Property { private $_id; // (PK) private $_ref_id; // the object reference id (FK) private $_name; // the name of the property private $_type; // 'string', 'int', 'float(n,m)', 'datetime', etc. private $_data; // ... // ..snip.. public getters/setters } Now, I need to perform some persistence on these objects. Some properties may be a text data type, but nothing bigger than what a varchar may hold. Also, later on, I need to be able to perform searches and sorting. Is it a good practice to use a single database table for this (ie. is there a non negligible performance impact)? If it's "acceptable", then what could be the data type for the data column?

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  • Turn based battle and formula

    - by Mark Chapman
    I'm building a game called DVP(Digimon Virtual Pet), and in this game other than taking care of your digimon, You can also battle and breed them. I'm working on the battle system (making it first cause the actual pet system will be easy compared to the netplay, or 39DLL)but here is the problem I don't want it to be "too" simple or "too" complicated, but I do want to go by a certain formula. There are str, def, spd, and int. Strength: How hard the attacking digimon is hitting Defense: How much damage your digimon can defend when being attacked Speed: The chance of you missing the enemy Intelligence (battle knowledge): The chance of you hitting a critical hit or defending a critical hit. I can make a super simple turn based example, but I don't know how exactly to make the formulas for what I've explained above, any help?

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  • C# - How to detect all IP addresses from a LAN?

    - by SAMIR BHOGAYTA
    string strHostName = string.Empty; cmbIPAddress.Items.Clear(); // Getting Ip address of local machine... // First get the host name of local machine. strHostName = Dns.GetHostName(); // Then using host name, get the IP address list.. IPHostEntry ipEntry = Dns.GetHostByName(strHostName); IPAddress[] iparrAddr = ipEntry.AddressList; if (iparrAddr.Length 0) { for (int intLoop = 0; intLoop cmbIPAddress.Items.Add(iparrAddr[intLoop].ToString()); }

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  • how to label a cuboid using open gl?

    - by usha
    hi this is how my 3dcuboid looks ,i have attached complete code , i want to label this cuboid using different name across sides how is it possible using opengl in android...plz help me out public class MyGLRenderer implements Renderer { Context context; Cuboid rect; private float mCubeRotation; // private static float angleCube = 0; // Rotational angle in degree for cube (NEW) // private static float speedCube = -1.5f; // Rotational speed for cube (NEW) public MyGLRenderer(Context context) { rect = new Cuboid(); this.context = context; } public void onDrawFrame(GL10 gl) { // TODO Auto-generated method stub gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT); gl.glLoadIdentity(); // Reset the model-view matrix gl.glTranslatef(0.2f, 0.0f, -8.0f); // Translate right and into the screen gl.glScalef(0.8f, 0.8f, 0.8f); // Scale down (NEW) gl.glRotatef(mCubeRotation, 1.0f, 1.0f, 1.0f); // gl.glRotatef(angleCube, 1.0f, 1.0f, 1.0f); // rotate about the axis (1,1,1) (NEW) rect.draw(gl); mCubeRotation -= 0.15f; //angleCube += speedCube; } public void onSurfaceChanged(GL10 gl, int width, int height) { // TODO Auto-generated method stub if (height == 0) height = 1; // To prevent divide by zero float aspect = (float)width / height; // Set the viewport (display area) to cover the entire window gl.glViewport(0, 0, width, height); // Setup perspective projection, with aspect ratio matches viewport gl.glMatrixMode(GL10.GL_PROJECTION); // Select projection matrix gl.glLoadIdentity(); // Reset projection matrix // Use perspective projection GLU.gluPerspective(gl, 45, aspect, 0.1f, 100.f); gl.glMatrixMode(GL10.GL_MODELVIEW); // Select model-view matrix gl.glLoadIdentity(); // Reset } public void onSurfaceCreated(GL10 gl, EGLConfig config) { // TODO Auto-generated method stub gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // Set color's clear-value to black gl.glClearDepthf(1.0f); // Set depth's clear-value to farthest gl.glEnable(GL10.GL_DEPTH_TEST); // Enables depth-buffer for hidden surface removal gl.glDepthFunc(GL10.GL_LEQUAL); // The type of depth testing to do gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST); // nice perspective view gl.glShadeModel(GL10.GL_SMOOTH); // Enable smooth shading of color gl.glDisable(GL10.GL_DITHER); // Disable dithering for better performance }} public class Cuboid{ private FloatBuffer mVertexBuffer; private FloatBuffer mColorBuffer; private ByteBuffer mIndexBuffer; private float vertices[] = { //width,height,depth -2.5f, -1.0f, -1.0f, 1.0f, -1.0f, -1.0f, 1.0f, 1.0f, -1.0f, -2.5f, 1.0f, -1.0f, -2.5f, -1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 1.0f, 1.0f, 1.0f, -2.5f, 1.0f, 1.0f }; private float colors[] = { // R,G,B,A COLOR 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.5f, 0.0f, 1.0f, 1.0f, 0.5f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f }; private byte indices[] = { // VERTEX 0,1,2,3,4,5,6,7 REPRESENTATION FOR FACES 0, 4, 5, 0, 5, 1, 1, 5, 6, 1, 6, 2, 2, 6, 7, 2, 7, 3, 3, 7, 4, 3, 4, 0, 4, 7, 6, 4, 6, 5, 3, 0, 1, 3, 1, 2 }; public Cuboid() { ByteBuffer byteBuf = ByteBuffer.allocateDirect(vertices.length * 4); byteBuf.order(ByteOrder.nativeOrder()); mVertexBuffer = byteBuf.asFloatBuffer(); mVertexBuffer.put(vertices); mVertexBuffer.position(0); byteBuf = ByteBuffer.allocateDirect(colors.length * 4); byteBuf.order(ByteOrder.nativeOrder()); mColorBuffer = byteBuf.asFloatBuffer(); mColorBuffer.put(colors); mColorBuffer.position(0); mIndexBuffer = ByteBuffer.allocateDirect(indices.length); mIndexBuffer.put(indices); mIndexBuffer.position(0); } public void draw(GL10 gl) { gl.glFrontFace(GL10.GL_CW); gl.glVertexPointer(3, GL10.GL_FLOAT, 0, mVertexBuffer); gl.glColorPointer(4, GL10.GL_FLOAT, 0, mColorBuffer); gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glEnableClientState(GL10.GL_COLOR_ARRAY); gl.glDrawElements(GL10.GL_TRIANGLES, 36, GL10.GL_UNSIGNED_BYTE, mIndexBuffer); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_COLOR_ARRAY); } } public class Draw3drect extends Activity { private GLSurfaceView glView; // Use GLSurfaceView // Call back when the activity is started, to initialize the view @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); glView = new GLSurfaceView(this); // Allocate a GLSurfaceView glView.setRenderer(new MyGLRenderer(this)); // Use a custom renderer this.setContentView(glView); // This activity sets to GLSurfaceView } // Call back when the activity is going into the background @Override protected void onPause() { super.onPause(); glView.onPause(); } // Call back after onPause() @Override protected void onResume() { super.onResume(); glView.onResume(); } }

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  • Breaking 1NF to model subset constraints. Does this sound sane?

    - by Chris Travers
    My first question here. Appologize if it is in the wrong forum but this seems pretty conceptual. I am looking at doing something that goes against conventional wisdom and want to get some feedback as to whether this is totally insane or will result in problems, so critique away! I am on PostgreSQL 9.1 but may be moving to 9.2 for this part of this project. To re-iterate: Does it seem sane to break 1NF in this way? I am not looking for debugging code so much as where people see problems that this might lead. The Problem In double entry accounting, financial transactions are journal entries with an arbitrary number of lines. Each line has either a left value (debit) or a right value (credit) which can be modelled as a single value with negatives as debits and positives as credits or vice versa. The sum of all debits and credits must equal zero (so if we go with a single amount field, sum(amount) must equal zero for each financial journal entry). SQL-based databases, pretty much required for this sort of work, have no way to express this sort of constraint natively and so any approach to enforcing it in the database seems rather complex. The Write Model The journal entries are append only. There is a possibility we will add a delete model but it will be subject to a different set of restrictions and so is not applicable here. If and when we allow deletes, we will probably do them using a simple ON DELETE CASCADE designation on the foreign key, and require that deletes go through a dedicated stored procedure which can enforce the other constraints. So inserts and selects have to be accommodated but updates and deletes do not for this task. My Proposed Solution My proposed solution is to break first normal form and model constraints on arrays of tuples, with a trigger that breaks the rows out into another table. CREATE TABLE journal_line ( entry_id bigserial primary key, account_id int not null references account(id), journal_entry_id bigint not null, -- adding references later amount numeric not null ); I would then add "table methods" to extract debits and credits for reporting purposes: CREATE OR REPLACE FUNCTION debits(journal_line) RETURNS numeric LANGUAGE sql IMMUTABLE AS $$ SELECT CASE WHEN $1.amount < 0 THEN $1.amount * -1 ELSE NULL END; $$; CREATE OR REPLACE FUNCTION credits(journal_line) RETURNS numeric LANGUAGE sql IMMUTABLE AS $$ SELECT CASE WHEN $1.amount > 0 THEN $1.amount ELSE NULL END; $$; Then the journal entry table (simplified for this example): CREATE TABLE journal_entry ( entry_id bigserial primary key, -- no natural keys :-( journal_id int not null references journal(id), date_posted date not null, reference text not null, description text not null, journal_lines journal_line[] not null ); Then a table method and and check constraints: CREATE OR REPLACE FUNCTION running_total(journal_entry) returns numeric language sql immutable as $$ SELECT sum(amount) FROM unnest($1.journal_lines); $$; ALTER TABLE journal_entry ADD CONSTRAINT CHECK (((journal_entry.running_total) = 0)); ALTER TABLE journal_line ADD FOREIGN KEY journal_entry_id REFERENCES journal_entry(entry_id); And finally we'd have a breakout trigger: CREATE OR REPLACE FUNCTION je_breakout() RETURNS TRIGGER LANGUAGE PLPGSQL AS $$ BEGIN IF TG_OP = 'INSERT' THEN INSERT INTO journal_line (journal_entry_id, account_id, amount) SELECT NEW.id, account_id, amount FROM unnest(NEW.journal_lines); RETURN NEW; ELSE RAISE EXCEPTION 'Operation Not Allowed'; END IF; END; $$; And finally CREATE TRIGGER AFTER INSERT OR UPDATE OR DELETE ON journal_entry FOR EACH ROW EXECUTE_PROCEDURE je_breaout(); Of course the example above is simplified. There will be a status table that will track approval status allowing for separation of duties, etc. However the goal here is to prevent unbalanced transactions. Any feedback? Does this sound entirely insane? Standard Solutions? In getting to this point I have to say I have looked at four different current ERP solutions to this problems: Represent every line item as a debit and a credit against different accounts. Use of foreign keys against the line item table to enforce an eventual running total of 0 Use of constraint triggers in PostgreSQL Forcing all validation here solely through the app logic. My concerns are that #1 is pretty limiting and very hard to audit internally. It's not programmer transparent and so it strikes me as being difficult to work with in the future. The second strikes me as being very complex and required a series of contraints and foreign keys against self to make work, and therefore it strikes me as complex, hard to sort out at least in my mind, and thus hard to work with. The fourth could be done as we force all access through stored procedures anyway and this is the most common solution (have the app total things up and throw an error otherwise). However, I think proof that a constraint is followed is superior to test cases, and so the question becomes whether this in fact generates insert anomilies rather than solving them. If this is a solved problem it isn't the case that everyone agrees on the solution....

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  • implementation of text editor in shell programming

    - by Arka Ghosh
    i have made a text editor in C. when i am changing the extension of that file from .c to .sh and compiling the file in the terminal,some error is shown,like for the global variables an external error is shown,and for the functions i have declared errors are shown there also.please help me to solve this. I am sending my code.. include include include int i,j,ec,fg,ec2; char fn[20],e,c,d; FILE *fp1,*fp2,fp; void Create(); void Append(); void Delete(); void Display(); int main() { do { printf("\n\t\t** TEXT EDITOR *"); printf("\n\n\tMENU:\n\t..\n "); printf("\n\t1.CREATE\n\t2.DISPLAY\n\t3.APPEND\n\t4.DELETE\n\t5.EXIT\n"); printf("\n\tEnter your choice: "); scanf("%d",&ec); switch(ec) { case 1: Create(); break; case 2: Display(); break; case 3: Append(); break; case 4: Delete(); break; case 5: exit(1); } }while(1); } void Create() { fp1=fopen("temp.txt","w"); printf("\n\tEnter the text and press '.' to save\n\n\t"); while(1) { c=getchar(); fputc(c,fp1); if(c == '.') { fclose(fp1); printf("\n\tEnter then new filename: "); scanf("%s",fn); fp1=fopen("temp.txt","r"); fp2=fopen(fn,"w"); while(!feof(fp1)) { c=getc(fp1); putc(c,fp2); } fclose(fp2); break; }} } void Display() { printf("\n\tEnter the file name: "); scanf("%s",fn); fp1=fopen(fn,"r"); if(fp1==NULL) { printf("\n\tFile not found!"); goto end1; } while(!feof(fp1)) { c=getc(fp1); printf("%c",c); } end1: fclose(fp1); printf("\n\n\tPress any key to continue.."); } void Delete() { printf("\n\tEnter the file name: "); scanf("%s",fn); fp1=fopen(fn,"r"); if(fp1==NULL) { printf("\n\tFile not found!"); goto end2; } fclose(fp1); if(remove(fn)==0) { printf("\n\n\tFile has been deleted successfully!"); goto end2; } else printf("\n\tError!\n"); end2: printf("\n\n\tPress any key to continue.."); getchar(); } void Append() { printf("\n\tEnter the file name: "); scanf("%s",fn); fp1=fopen(fn,"r"); if(fp1==NULL) { printf("\n\tFile not found!"); goto end3; } while(!feof(fp1)) { c=getc(fp1); printf("%c",c); } fclose(fp1); printf("\n\tType the text and press 'Ctrl+s' to append.\n"); fp1=fopen(fn,"a"); while(1) { c=getchar(); if(c==19) goto end3; if(c==13) { d='\n'; fputc(d,fp1); } else { fputc(c,fp1); } } end3: fclose(fp1); }

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