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• Where do I put the logic of my MFC program?

  - by Matthew

  I created an application core, in C++, that I've compiled into a static library in Visual Studio. I am now at the process of writing a GUI for it. I am using MFC to do this. I figured out how to map button presses to execute certain methods of my application core's main class (i.e. buttons to have it start and stop). The core class however, should always be sampling data from an external source every second or two. The GUI should then populate some fields after each sample is taken. I can't seem to find a spot in my MFC objects like CDialog that I can constantly check to see if my class has grabbed the data.. then if it has put that data into some of the text boxes. A friend suggested that I create a thread on the OnInit() routine that would take care of this, but that solution isn't really working for me. Is there no spot where I can put an if statement that keeps being called until the program quits? i.e. if( coreapp.dataSampleReady() ) { // put coreapp.dataItem1() in TextBox1 // set progress bar to coreapp.dataItem2() // etc. // reset dataSampleReady }

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• Is it possible to spoof or reuse VIEWSTATE or detect if it is protected from modification?

  - by Peter Jaric

  Question ASP and ASP.NET web applications use a value called VIEWSTATE in forms. From what I understand, this is used to persist some kind of state on the client between requests to the web server. I have never worked with ASP or ASP.NET and need some help with two questions (and some sub-questions): 1) Is it possible to programmatically spoof/construct a VIEWSTATE for a form? Clarification: can a program look at a form and from that construct the contents of the base64-encoded VIEWSTATE value? 1 a) Or can it always just be left out? 1 b) Can an old VIEWSTATE for a particular form be reused in a later invocation of the same form, or would it just be luck if that worked? 2) I gather from http://msdn.microsoft.com/en-us/library/ms972976.aspx#viewstate_topic12 that it is possible to turn on security so that the VIEWSTATE becomes secure from spoofing. Is it possible for a program to detect that a VIEWSTATE is safeguarded in such a way? 2 a) Is there a one-to-one mapping between the occurrence of EVENTVALIDATION values and secure VIEWSTATEs? Regarding 1) and 2), if yes, can I have a hint about how I would do that? For 2) I am thinking I could base64-decode the value and search for a string that always is found in unencrypted VIEWSTATEs. "First:"? Something else? Background I have made a small tool for detecting and exploiting so called CSRF vulnerabilities. I use it to quickly make proof of concepts of such vulnerabilities that I send to the affected site owners. Quite often I encounter these forms with a VIEWSTATE, and these I don't know if they are secure or not. Edit 1: Clarified question 1 somewhat. Edit 2: Added text in italics.

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• LDAP/AD Integrated Group/Membership Management Package suitable for embedding in an application

  - by Ernest

  In several web applications, it is often necessary to define groups of users for purposes of membership as well as role management. For example, in one of our applications we would like to user a group of "Network Engineers" and another group that consists of "Managers" of such Network Engineers. The information we need is contact details of members of each group. So far, we have written our own tools to allow the administrator of the application to add/delete/move groups and their memberships and either store them in a XML file or a database. Increasingly, companies already have the groups we want defined in LDAP/AD, so it would be best to create a pointer in our application to the correspoding group in LDAP. Although there are a number of LDAP libraries and LDAP browsers available and we could code this and provide a web front end to get a list of available groups and their members, we are wondering if there is already a "component framework" available that would readily provide this LDAP browsing functionality that we could just embed this into our application. Something between a library and a full LDAP browser product ? (To clarify, the use case is for an admin of our web application to create a locally relevant group name and then map it to an exiting LDAP group. To enable this in the UI, we would like to present a way for the admin to browse available groups in the company LDAP server, view their membership, and select the LDAP group they would like to map to the locally relevant group name. In a second step, we would then synchronize the members of that LDAP group and their contact details to a store in our application ) Appreciate any pointers.

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• What is your personal approach/take on commenting?

  - by Trae

  Duplicate What are your hard rules about commenting? A Developer I work with had some things to say about commenting that were interesting to me (see below). What is your personal approach/take on commenting? "I don't add comments to code unless its a simple heading or there's a platform-bug or a necessary work-around that isn't obvious. Code can change and comments may become misleading. Code should be self-documenting in its use of descriptive names and its logical organization - and its solutions should be the cleanest/simplest way to perform a given task. If a programmer can't tell what a program does by only reading the code, then he's not ready to alter it. Commenting tends to be a crutch for writing something complex or non-obvious - my goal is to always write clean and simple code." "I think there a few camps when it comes to commenting, the enterprisey-type who think they're writing an API and some grand code-library that will be used for generations to come, the craftsman-like programmer that thinks code says what it does clearer than a comment could, and novices that write verbose/unclear code so as to need to leave notes to themselves as to why they did something."

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• Simplification / optimization of GPS track

  - by GreyCat

  I've got a GPS track, produces by gpxlogger(1) (supplied as a client for gpsd). GPS receiver updates its coordinates every 1 second, gpxlogger's logic is very simple, it writes down location (lat, lon, ele) and a timestamp (time) received from GPS every n seconds (n = 3 in my case). After writing down a several hours worth of track, gpxlogger saves several megabyte long GPX file that includes several thousands of points. Afterwards, I try to plot this track on a map and use it with OpenLayers. It works, but several thousands of points make using the map a sloppy and slow experience. I understand that having several thousands of points of suboptimal. There are myriads of points that can be deleted without losing almost anything: when there are several points making up roughly the straight line and we're moving with the same constant speed between them, we can just leave the first and the last point and throw anything else. I thought of using gpsbabel for such track simplification / optimization job, but, alas, it's simplification filter works only with routes, i.e. analyzing only geometrical shape of path, without timestamps (i.e. not checking that the speed was roughly constant). Is there some ready-made utility / library / algorithm available to optimize tracks? Or may be I'm missing some clever option with gpsbabel?

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• define a closure as method from class

  - by user272839

  Hi, i'm trying to play with php5.3 and closure. I see here (Listing 7. Closure inside an object : http://www.ibm.com/developerworks/opensource/library/os-php-5.3new2/index.html) that it's possible to use $this in the callback function, but it's not. So I try to give $this as use variable : $self = $this; $foo = function() use($self) { //do something with $self } So to use the same example : class Dog { private $_name; protected $_color; public function __construct($name, $color) { $this->_name = $name; $this->_color = $color; } public function greet($greeting) { $self = $this; return function() use ($greeting, $self) { echo "$greeting, I am a {$self->_color} dog named {$self->_name}."; }; } } $dog = new Dog("Rover","red"); $dog->greet("Hello"); Output: Hello, I am a red dog named Rover. First of all this example does not print the string but return the function, but that's not my problem. Secondly I can't access to private or protected, because the callback function is a global function and not in the context from the Dog object. Tha't my problem. It's the same as : function greet($greeting, $object) { echo "$greeting, I am a {$self->_color} dog named {$self->_name}."; } And I want : public function greet($greeting) { echo "$greeting, I am a {$self->_color} dog named {$self->_name}."; } Which is from Dog and not global. I hope that I am clear ...

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• Codeigniter Session Data not available in other pages after login

  - by jswat

  So, I have set up a login page that verifies the user's credentials, and then sets codeigniter session data 'email' and 'is_logged_in' and a few other items. The first page after the login, the data is accessible. After that page, I can no longer access the session data. In fact, if I try reloading that first page, the session data is gone. I have tried storing it in the database, storing it unencrypted (bad idea I know, but it was for troubleshooting), and storing it encrypted. I have autoloaded the session library in config.php. Here's an example of the code I'm using to set the session data: $data = array( 'email' => $this->input->post('username'), 'is_logged_in' => true ); $this->session->set_userdata($data); And to retrieve it, I'm using : $this->session->userdata('email'); Or $this->session->userdata('is_logged_in'); I've done lots of work with PHP and cookies, and sessions before, but this is my first project with Codeigniter and I'm perplexed. Could it have something to do with directory issues? I have the login page and process controlled by a 'login' controller, and then it redirects to a 'site' controller. Thanks for your help, and please let me know if I need to clarify anything.

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• jQuery "best practices" is an oxymoron [closed]

  - by n00b

  jQuery "best practices", oxymoron for several reasons sadly To speak candidly, the entire jQuery library has a HIGHLY inconsistent API, and virtually no coding standards. It's basically a subset of JavaScript, a new language if you will, which is probably the most confusing part for normal javascript developers. In my opinion, use normal JavaScript where possible to save on memory consumption. Or, better yet, use a professional tool like YUI. If you already come from a javascript background, you will appreciate it much more than jQuery because it doesn't have n00b wrappers around everything. In tools like YUI, you interact directly with the native DOM to do things, instead of a super-jQuery object that tries to do everything. I'll get voted down for saying the truth. Don't get me wrong, jQuery is cool if you wanna throw something flashy up quick, but if you're going to build a larger app you're going to need a more refined tool (especially since jQuery leaks memory like no other once you start chaining too much things). jQuery does have one of the lowest learning curves, and you won't outgrow it for awhile, but when you do it will be highly apparent and tedious to merge to something else. over 60 years programming experience someone clean this up and community wiki please

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• Which compiler option I should choose?

  - by Surjya Narayana Padhi

  Hi Geeks, I have to use the third party static library for my qt application to run on windows. The third party provides me a .lib and .h file for use. These libraries are compiled with MSVC compiler. My qt Creator is using MinGW compiler to compile my application. I copied the .h and .lib file to my qt project directory and then added those in .pro file as follows QT += core gui TARGET = MyTest TEMPLATE = app LIBS += C:\Qt\2010.05\qt\MyTest\newApi.lib SOURCES += main.cpp\ mainwindow.cpp HEADERS += mainwindow.h \ newApi.h FORMS += mainwindow.ui Now I am getting some runtime error like this - Starting C:\Qt\2010.05\qt\MyTest-build-desktop\debug\MyTest.exe... C:\Qt\2010.05\qt\MyTest-build-desktop\debug\MyTest.exe exited with code -1073741515 Can any body suggest is this runtime error is due to mismatch of compiler? (because of my .lib file I added is comipled in MSVC compiler and my qt app is compiled using MinGW compiler) If not what may be the reason? Am I missing anything in adding the .h and .lib file to my qt project? If my MinGW compiler will not support the .lib file generated in MSVC compiler what may be the work-arround? Can I create the .lib files in MinGW compiler? or this format is supported only by MSVC compiler only? Please suggest...

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• Importing external .jar file to Android project

  - by robintw

  I've read various answers to similar questions on StackOverflow, so I apologise if I'm repeating another question, but I can't seem to get this to work. I have a standard java project in which I've written code to parse some BBC Radio XML data from the internet. The project is called BBCSchedules and the class I'm interested in is called BBCChannel. I'm now trying to use the BBCChannel class in an android application. How should I go about doing this? I've tried various things, following various bits of advice on the internet, and the place I've got to at the moment is compiling my BBCSchedules project to a .jar file, and importing that to the Android project using the Build Path/Library/Add External Jar option. However, Eclispe still doesn't recognise the BBCChannel class, and won't let me run the application because of this. I guess I've done something silly wrong, but what is it? Cheers, Robin UPDATE: I've tried the steps listed in http://stackoverflow.com/questions/1334802/how-can-i-use-external-jars-in-an-android-project and various other StackOverflow questions I can find that seem to be related to this, but absolutely nothing seems to work. Any other ideas? UPDATE: The discussions I've had with the author of the first answer below suggest that it is something to do with how I am using Eclipse to attach the .jar file. The project he sent me with the .jar file already attached didn't work. Any other ideas anyone?

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• issue with vhdl structural coding

  - by user3699982

  The code below is a simple vhdl structural architecture, however, the concurrent assignment to the signal, comb1, is upsetting the simulation with the outputs (tb_lfsr_out) and comb1 becoming undefined. Please, please help, thank you, Louise. library IEEE; use IEEE.STD_LOGIC_1164.all; entity testbench is end testbench; architecture behavioural of testbench is CONSTANT clock_frequency : REAL := 1.0e9; CONSTANT clock_period : REAL := (1.0/clock_frequency)/2.0; signal tb_master_clk, comb1: STD_LOGIC := '0'; signal tb_lfsr_out : std_logic_vector(2 DOWNTO 0) := "111"; component dff port ( q: out STD_LOGIC; d, clk: in STD_LOGIC ); end component; begin -- Clock/Start Conversion Generator tb_master_clk <= (NOT tb_master_clk) AFTER (1 SEC * clock_period); comb1 <= tb_lfsr_out(0) xor tb_lfsr_out(2); dff6: dff port map (tb_lfsr_out(2), tb_lfsr_out(1), tb_master_clk); dff7: dff port map (tb_lfsr_out(1), tb_lfsr_out(0), tb_master_clk); dff8: dff port map (tb_lfsr_out(0), comb1, tb_master_clk); end behavioural;

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• form:select items problem in spring mvc portlet

  - by dhaval

  I have a set of drop-down control which I want to render with my custom tag library. The following is the code of the tag lib: <spring:bind path="${path}"> <c:choose> <c:when test="${readOnly}"> <span class="readOnly">${status.value}</span> </c:when> <c:otherwise> <form:select path="${path }" itemLabel="${label }" itemValue="${value }" items="${itemList}"> </form:select> </c:otherwise> </c:choose> And this is the code I have written in the JSP file: <tag:conditionalListControl path="model.selectedCountry" readOnly="false" label="name" value="id" listItems="model.countryList" className="simple" /> Upon execution the paring returns the following error: [jsp:165] javax.servlet.jsp.JspException: Type [java.lang.String] is not valid for option items But if i change the items="${itemList}" to items="${model.countryList}" which is the list I want to display, it works fine without any problem and also bind to required variables on form submit. But i don't want to hard code any variables in the tag lib. Any suggestions???

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• Java method help

  - by dalton conley

  Ok, so I'm working on a project for a class I'm taking.. simple music library. Now I'm having some issues, the main issue is I'm getting "non-static method cannot be referenced from a static context" Here is a function I have public void addSong() { Scanner scan = new Scanner(System.in); Song temp = new Song(); int index = countFileLines(Main.databaseFile); index = index + 2; temp.index = index; System.out.print("Enter the artist name: "); temp.artist.append(scan.next()); } Now thats in a class file called LibraryFunctions. So I can access it with LibraryFunctions.addSong(); Now I'm trying to run this in my main java file and its giving me the error, I know why the error is happening, but what do I do about it? If I make addSong() a static function then it throws errors at me with the Song temp = new Song() being static. Kind of ironic. Much help is appreciated on this!

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• Faster quadrature decoder loops with Python code

  - by Kelei

  I'm working with a BeagleBone Black and using Adafruit's IO Python library. Wrote a simple quadrature decoding function and it works perfectly fine when the motor runs at about 1800 RPM. But when the motor runs at higher speeds, the code starts missing some of the interrupts and the encoder counts start to accumulate errors. Do you guys have any suggestions as to how I can make the code more efficient or if there are functions which can cycle the interrupts at a higher frequency. Thanks, Kel Here's the code: # Define encoder count function def encodercount(term): global counts global Encoder_A global Encoder_A_old global Encoder_B global Encoder_B_old global error Encoder_A = GPIO.input('P8_7') # stores the value of the encoders at time of interrupt Encoder_B = GPIO.input('P8_8') if Encoder_A == Encoder_A_old and Encoder_B == Encoder_B_old: # this will be an error error += 1 print 'Error count is %s' %error elif (Encoder_A == 1 and Encoder_B_old == 0) or (Encoder_A == 0 and Encoder_B_old == 1): # this will be clockwise rotation counts += 1 print 'Encoder count is %s' %counts print 'AB is %s %s' % (Encoder_A, Encoder_B) elif (Encoder_A == 1 and Encoder_B_old == 1) or (Encoder_A == 0 and Encoder_B_old == 0): # this will be counter-clockwise rotation counts -= 1 print 'Encoder count is %s' %counts print 'AB is %s %s' % (Encoder_A, Encoder_B) else: #this will be an error as well error += 1 print 'Error count is %s' %error Encoder_A_old = Encoder_A # store the current encoder values as old values to be used as comparison in the next loop Encoder_B_old = Encoder_B # Initialize the interrupts - these trigger on the both the rising and falling GPIO.add_event_detect('P8_7', GPIO.BOTH, callback = encodercount) # Encoder A GPIO.add_event_detect('P8_8', GPIO.BOTH, callback = encodercount) # Encoder B # This is the part of the code which runs normally in the background while True: time.sleep(1)

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• How can I accelerate the generation of the an MD5 Checksum within vb.net?

  - by Richard

  I'm working with some very large files residing on P2 (Panasonic) cards. Part of the process we employ is to first generate a checksum of the file we are going to copy, then copy the file, then run a checksum on the file to confirm that it copied OK. The problem is, is that files are large (70 GB+) and take a long time to complete. It's an issue since we will eventually be dealing with thousands of these files. I would like to find a faster way to generate the checksum other than using the System.Security.Cryptography.MD5CryptoServiceProvider I don't care if this means using a specialized hardware card, provided it works and is not to ungodly expensive. I would prefer to have a method of encoding that provided some feedback as to how far the process has gone along so I can display it like I do now. The application is written in vb.net. I would prefer to be able to use it as component, library, reference within my application, but I'm willing to call an outside application if there is enough improvement in the speed of generating the checksum. Needless to say, the checksum must be consistent and correct. :-) Thank you in advance for your time and efforts, Richard

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• Using sigprocmask to implement locks

  - by EpsilonVector

  I'm implementing user threads in Linux kernel 2.4, and I'm using ualarm to invoke context switches between the threads. We have a requirement that our thread library's functions should be uninterruptable, so I looked into blocking signals and learned that using sigprocmask is the standard way to do this. However, it looks like I need to do quite a lot to implement this: sigset_t new_set, old_set; sigemptyset(&new_set); sigaddset(&new_set, SIGALRM); sigprocmask(SIG_BLOCK, &new_set, &old_set); This blocks SIGALARM but it does this with 3 function invocations! A lot can happen in the time it takes for these functions to run, including the signal being sent. The best idea I had to mitigate this was temporarily disabling ualarm, like this: sigset_t new_set, old_set; time=ualarm(0,0); sigemptyset(&new_set); sigaddset(&new_set, SIGALRM); sigprocmask(SIG_BLOCK, &new_set, &old_set); ualarm(time, 0); Which is fine except that this feels verbose. Isn't there a better way to do this?

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• How does one gets started with Winforms style applications on Win32?

  - by Billy ONeal

  EDIT: I'm extremely tired and frustrated at the moment -- please ignore that bit in this question -- I'll edit it in the morning to be better. Okay -- a bit of background: I'm a C++ programmer mostly, but the only GUI stuff I've ever done was on top of .NET's WinForms platform. I'm completely new to Windows GUI programming, and despite Petzold's excellent book, I'm extremely confused. Namely, it seems that most every reference on getting started with Win32 is all about drawing lines and curves and things -- a topic about which (at least at present time) I couldn't care less. I need a checked list box, a splitter, and a textbox -- something that would take less than 10 minutes to do in Winforms land. It has been recommended to me to use the WTL library, which provides an implementation of all three of these controls -- but I keep getting hung up on simple things, such as getting the damn controls to use the right font, and getting High DPI working correctly. I've spent two freaking days on this, and I can't help but think there has to be a better reference for these kinds of things than I've been able to find. Petzold's book is good, but it hasn't been updated since Windows 95 days, and there's been a LOT changed w.r.t. how applications should be correctly developed since it was published. I guess what I'm looking for is a modern Petzold book. Where can I find such a resource, if any?

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• C++: Efficiently adding integers to strings

  - by Shinka

  I know how to add integers to strings, but I'm not sure I'm doing it in an efficient matters. I have a class where I often have to return a string plus an integer (a different integer each time), in Java I would do something like public class MyClass { final static String S = "MYSTRING"; private int id = 0; public String getString() { return S + (id++); } } But in C++ I have to do; class MyClass { private: std::string S; // For some reason I can't do const std::string S = "MYSTRING"; int id; public: MyClass() { S = "MYSTRING"; id = 0; } std::string getString() { std::ostringstream oss; oss << S << id++; return oss.str(); } } An additional constraint: I don't want (in fact, in can't) use Boost or any other librairies, I'll have to work with the standard library. So the thing is; the code works, but in C++ I have to create a bunch of ostringstream objects, so it seems inefficient. To be fair, perhaps Java do the same and I just don't notice it, I say it's inefficient mostly because I know very little about strings. Is there a more efficient way to do this ?

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• Accents in uploaded file being replaced with '?'

  - by Katfish

  I am building a data import tool for the admin section of a website I am working on. The data is in both French and English, and contains many accented characters. Whenever I attempt to upload a file, parse the data, and store it in my MySQL database, the accents are replaced with '?'. I have text files containing data (charset is iso-8859-1) which I upload to my server using CodeIgniter's file upload library. I then read the file in PHP. My code is similar to this: $this->upload->do_upload() $data = array('upload_data' => $this->upload->data()); $fileHandle = fopen($data['upload_data']['full_path'], "r"); while (($line = fgets($fileHandle)) !== false) { echo $line; } This produces lines with accents replaced with '?'. Everything else is correct. If I download my uploaded file from my server over FTP, the charset is still iso-8850-1, but a diff reveals that the file has changed. However, if I open the file in TextEdit, it displays properly. I attempted to use PHP's stream_encoding method to explicitly set my file stream to iso-8859-1, but my build of PHP does not have the method. After running out of ideas, I tried wrapping my strings in both utf8_encode and utf8_decode. Neither worked. If anyone has any suggestions about things I could try, I would be extremely grateful.

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• reading newlines with FORMAT statement

  - by peter.murray.rust

  I'm writing a preprocessor and postprocessor for Fortran input and output using FORMAT-like statements (there are reasons not to use a FORTRAN library). I want to treat the new line ("/") character correctly. I don't have a Fortran compiler immediately to hand. Is there a simple algorithm for working out how many newlines are written or consumed (This post just gives reading examples) [Please assume a FORTRAN77-like mentality in the FORTRAN code and correct any FORTRAN syntax on my part] UPDATE: no comments yet so I am reduced to finding a compiler and running it myself. I'll post the answers if I'm not beaten to it. No-one commented I had the format syntax wrong. I've changed it but there may still be errors Assume datafile 1 a b c d etc... (a) does the READ command always consume a newline? does READ(1, '(A)') A READ(1, '(A)') B give A='a' and B='b' (b) what does READ(1,'(A,/)') A READ(1,'(A)') B give for B? (I would assume 'c') (c) what does READ(1, '(/)') READ(1, '(A)') A give for A (is it 'b' or 'c') (d) what does READ(1,'(A,/,A)') A, B READ(1,'(A)') C give for A and B and C(can I assume 'a' and 'b' and 'c') (e) what does READ(1,'(A,/,/,A)') A, B READ(1,'(A)') C give for A and B and C(can I assume 'a' and 'c' and 'd')? Are there any cases in which the '/' is redundant?

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• Goldbach theory in C

  - by nofe

  I want to write some code which takes any positive, even number (greater than 2) and gives me the smallest pair of primes that sum up to this number. I need this program to handle any integer up to 9 digits long. My aim is to make something that looks like this: Please enter a positive even integer ( greater than 2 ) : 10 The first primes adding : 3+7=10. Please enter a positive even integer ( greater than 2 ) : 160 The first primes adding : 3+157=160. Please enter a positive even integer ( greater than 2 ) : 18456 The first primes adding : 5+18451=18456. I don't want to use any library besides stdio.h. I don't want to use arrays, strings, or anything besides for the most basic toolbox: scanf, printf, for, while, do-while, if, else if, break, continue, and the basic operators (<,, ==, =+, !=, %, *, /, etc...). Please no other functions especially is_prime. I know how to limit the input to my needs so that it loops until given a valid entry. So now I'm trying to figure out the algorithm. I thought of starting a while loop like something like this: #include <stdio.h> long first, second, sum, goldbach, min; long a,b,i,k; //indices int main (){ while (1){ printf("Please enter a positive integer :\n"); scanf("%ld",&goldbach); if ((goldbach>2)&&((goldbach%2)==0)) break; else printf("Wrong input, "); } while (sum!=goldbach){ for (a=3;a<goldbach;a=(a+2)) for (i=2;(goldbach-a)%i;i++) first = a; for (b=5;b<goldbach;b=(b+2)) for (k=2;(goldbach-b)%k;k++) sum = first + second; } }

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• Simple App Engine Sessions Implementation

  - by raz0r

  Here is a very basic class for handling sessions on App Engine: """Lightweight implementation of cookie-based sessions for Google App Engine. Classes: Session """ import os import random import Cookie from google.appengine.api import memcache _COOKIE_NAME = 'app-sid' _COOKIE_PATH = '/' _SESSION_EXPIRE_TIME = 180 * 60 class Session(object): """Cookie-based session implementation using Memcached.""" def __init__(self): self.sid = None self.key = None self.session = None cookie_str = os.environ.get('HTTP_COOKIE', '') self.cookie = Cookie.SimpleCookie() self.cookie.load(cookie_str) if self.cookie.get(_COOKIE_NAME): self.sid = self.cookie[_COOKIE_NAME].value self.key = 'session-' + self.sid self.session = memcache.get(self.key) if self.session: self._update_memcache() else: self.sid = str(random.random())[5:] + str(random.random())[5:] self.key = 'session-' + self.sid self.session = dict() memcache.add(self.key, self.session, _SESSION_EXPIRE_TIME) self.cookie[_COOKIE_NAME] = self.sid self.cookie[_COOKIE_NAME]['path'] = _COOKIE_PATH print self.cookie def __len__(self): return len(self.session) def __getitem__(self, key): if key in self.session: return self.session[key] raise KeyError(str(key)) def __setitem__(self, key, value): self.session[key] = value self._update_memcache() def __delitem__(self, key): if key in self.session: del self.session[key] self._update_memcache() return None raise KeyError(str(key)) def __contains__(self, item): try: i = self.__getitem__(item) except KeyError: return False return True def _update_memcache(self): memcache.replace(self.key, self.session, _SESSION_EXPIRE_TIME) I would like some advices on how to improve the code for better security. Note: In the production version it will also save a copy of the session in the datastore. Note': I know there are much more complete implementations available online though I would like to learn more about this subject so please don't answer the question with "use that" or "use the other" library.

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• Unusual heap size limitations in VS2003 C++

  - by Shane MacLaughlin

  I have a C++ app that uses large arrays of data, and have noticed while testing that it is running out of memory, while there is still plenty of memory available. I have reduced the code to a sample test case as follows; void MemTest() { size_t Size = 500*1024*1024; // 512mb if (Size > _HEAP_MAXREQ) TRACE("Invalid Size"); void * mem = malloc(Size); if (mem == NULL) TRACE("allocation failed"); } If I create a new MFC project, include this function, and run it from InitInstance, it works fine in debug mode (memory allocated as expected), yet fails in release mode (malloc returns NULL). Single stepping through release into the C run times, my function gets inlined I get the following // malloc.c void * __cdecl _malloc_base (size_t size) { void *res = _nh_malloc_base(size, _newmode); RTCCALLBACK(_RTC_Allocate_hook, (res, size, 0)); return res; } Calling _nh_malloc_base void * __cdecl _nh_malloc_base (size_t size, int nhFlag) { void * pvReturn; // validate size if (size > _HEAP_MAXREQ) return NULL; ' ' And (size _HEAP_MAXREQ) returns true and hence my memory doesn't get allocated. Putting a watch on size comes back with the exptected 512MB, which suggests the program is linking into a different run-time library with a much smaller _HEAP_MAXREQ. Grepping the VC++ folders for _HEAP_MAXREQ shows the expected 0xFFFFFFE0, so I can't figure out what is happening here. Anyone know of any CRT changes or versions that would cause this problem, or am I missing something way more obvious?

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• How can I get a iterable resultset from the database using pdo, instead of a large array?

  - by Tchalvak

  I'm using PDO inside a database abstraction library function query. I'm using fetchAll(), which if you have a lot of results, can get memory intensive, so I want to provide an argument to toggle between a fetchAll associative array and a pdo result set that can be iterated over with foreach and requires less memory (somehow). I remember hearing about this, and I searched the PDO docs, but I couldn't find any useful way to do that. Does anyone know how to get an iterable resultset back from PDO instead of just a flat array? And am I right that using an iterable resultset will be easier on memory? I'm using Postgresql, if it matters in this case. . . . The current query function is as follows, just for clarity. /** * Running bound queries on the database. * * Use: query('select all from players limit :count', array('count'=>10)); * Or: query('select all from players limit :count', array('count'=>array(10, PDO::PARAM_INT))); **/ function query($sql_query, $bindings=array()){ DatabaseConnection::getInstance(); $statement = DatabaseConnection::$pdo->prepare($sql_query); foreach($bindings as $binding => $value){ if(is_array($value)){ $statement->bindParam($binding, $value[0], $value[1]); } else { $statement->bindValue($binding, $value); } } $statement->execute(); // TODO: Return an iterable resultset here, and allow switching between array and iterable resultset. return $statement->fetchAll(PDO::FETCH_ASSOC); }

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• Thread management advice - Is TPL a good idea?

  - by Ian

  I'm hoping to get some advice on the use of thread managment and hopefully the task parallel library, because I'm not sure I've been going down the correct route. Probably best is that I give an outline of what I'm trying to do. Given a Problem I need to generate a Solution using a heuristic based algorithm. I start of by calculating a base solution, this operation I don't think can be parallelised so we don't need to worry about. Once the inital solution has been generated, I want to trigger n threads, which attempt to find a better solution. These threads need to do a couple of things: They need to be initalized with a different 'optimization metric'. In other words they are attempting to optimize different things, with a precedence level set within code. This means they all run slightly different calculation engines. I'm not sure if I can do this with the TPL.. If one of the threads finds a better solution that the currently best known solution (which needs to be shared across all threads) then it needs to update the best solution, and force a number of other threads to restart (again this depends on precedence levels of the optimization metrics). I may also wish to combine certain calculations across threads (e.g. keep a union of probabilities for a certain approach to the problem). This is probably more optional though. The whole system needs to be thread safe obviously and I want it to be running as fast as possible. I tried quite an implementation that involved managing my own threads and shutting them down etc, but it started getting quite complicated, and I'm now wondering if the TPL might be better. I'm wondering if anyone can offer any general guidance? Thanks...

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