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  • how do I use an enum value on a switch statement in C++

    - by BotBotPgm
    I would like to use an enum value for my switch statment in C++. Is it possible to use the enum values enclosed in the "{}" as choices for the "switch()"? I know that switch() needs an integer value in order to direct the flow of programming to the appropriate case number. If this is the case, do I just make a variable for each constant in the 'enum' statment? I also want the user to be able to pick the choice and pass that choice to the switch() statement. for example: cout<< "1 - Easy"; cout<<"2 - Medium"; cout<< "3 -Hard"; enum myChoice {EASY =1 ,MEDIUM = 2, HARD = 3} cin ???? switch(????) case 1/EASY: (can I just type case EAST?) cout << "You picked easy!"; break; case 2/MEDIUM: cout << "You picked medium!"; case 3..... (same thing as case 2 except on hard.) default: return 0; Thanks

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  • Making firefox refresh images faster

    - by Earlz
    I have a thing I'm doing where I need a webpage to stream a series of images from the local client computer. I have a very simple run here: http://jsbin.com/idowi/34 The code is extremely simple setTimeout ( "refreshImage()", 100 ); function refreshImage(){ var date = new Date() var ticks = date.getTime() $('#image').attr('src','http://127.0.0.1:2723/signature?'+ticks.toString()); setTimeout ("refreshImage()", 100 ); } Basically I have a signature pad being used on the client machine. We want for the signature to show up in the web page and for them to see themselves signing it within the web page(the pad does not have an LCD to show it to them right there). So I setup a simple local HTTP server which grabs an image of what the current state of the signature pad looks like and it gets sent to the browser. This has no problems in any browser(tested in IE7, 8, and Chrome) but Firefox where it is extremely laggy and jumpy and doesn't keep with the 10 FPS rate. Does anyone have any ideas on how to fix this? I've tried creating very simple double buffering in javascript but that just made things worse. Also for a bit more information it seems that Firefox is executing the javascript at the correct framerate as on the server the requests are coming in at a constant speed. But the images are only refreshed inconsistently ranging from 5 times per second all the way down to 0 times per second(taking 2 seconds to do a refresh) Also I have tried using different image formats all with the same results. The formats I've tried include bitmaps, PNGs, and GIFs (GIFs caused a minor problem in Chrome with flicker though) Could it be possible that Firefox is somehow caching my images causing a slight lag? I send these headers though: Pragma-directive: no-cache Cache-directive: no-cache Cache-control: no-cache Pragma: no-cache Expires: 0

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  • How to track a projects extraneous quirks

    - by Steerpike
    Hello, It's possible that the answer to this question may just be standard bug tracking software like jira or fogbugz, but I'm kind of hoping someone out there knows a better system for what I'm describing. My most current project is requiring a lot of setup quirkiness to get into a position where I can actually start a coding section. For example: A series of convoluted internal company commands before I can insitgate an SSH. Making sure any third party classes that make external calls have internal company proxy options setup - while also making sure these setting wont be set up when installed on a production environment Making sure the proxy is set before trying to install pear packages. Other similar things, mostly involving internal IT security and getting it to work with modules and packages. Individually none of these things is a huge deal, and I've written extensive notes to myself regarding exact commands and aditions I've made, but they're currently in a general text document and it's going to be hard to remember exactly where what I need is far down the line. We also have several new staff starting soon and I' rather give them an easier time of setting up their programming environments. Like I said, they aren't 'programming quirks' exactly, but just the constant fiddling that comes about before programming starts in earnest. Any thoughts on the best way to documents these things for my own and future generations sanity?

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  • 3 small PHP errors I cannot decipher

    - by Dave
    *Notice: Use of undefined constant _ - assumed '_' in /.../uploader.php on line 45* Line 45 $newname = str_replace(array(' ', '&'), array('_', 'and'), trim( strip_tags( $_POST['name'] ) ) ) . _ . $formKey->generateKey() . '_' . time() . '.jpg'; Notice: Undefined index: approve in /.../uploader.php on line 81 Line 81 - the second last line here $query = sprintf("INSERT INTO `$db_name`.`the_table` (`id` , `name` , `photo` , `email` , `date` , `code` , `subscribe` , `approve` , `created` ) VALUES ( NULL , '%s', '%s', '%s', '%s', '%s', '%s', '1', CURRENT_TIMESTAMP );", mysql_real_escape_string($_POST['name']), mysql_real_escape_string($newname), mysql_real_escape_string($_POST['email']), mysql_real_escape_string($date), mysql_real_escape_string($_POST['code']), mysql_real_escape_string($subscribe), mysql_real_escape_string($_POST['approve']) ); Warning: Cannot modify header information - headers already sent by (output started at /.../uploader.php:45) in/.../uploader.php on line 102 Line 45 $newname = str_replace(array(' ', '&'), array('_', 'and'), trim( strip_tags( $_POST['name'] ) ) ) . _ . $formKey->generateKey() . '_' . time() . '.jpg'; Line 102 - the third line here if ($success == 'Done') { $page = 'uploader'; header('Location: ./thanks.php'); } else { echo "error"; }

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  • Imbricated C++ template

    - by gregseth
    I have the following pattern: template <int a, int b> class MyClass { template <int c> MyClass<a, c> &operator*(MyClass<c, b> const &other) const; }; // ../.. template <int a, int b> template <int c> MyClass<a, c> &MyClass<a, b>::operator*(MyClass<c, b> const &other) const { MyClass<a, c> result; // ..do stuff.. return result; } It doesn't compile, the error message is Error C2975. invalid template argument 'number', constant expression expected. If I replace template <int c> by template <int c, int d> and use it accordignly, it works fine. But I want d to be the same value as b. My questions: Why the example doesn't work? How can I enforce d to be the same than b? Thanks.

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  • Encode_JSON Errors in Lasso 8.6.2 After Period of Time

    - by ATP_JD
    We are in the process of converting apps from Lasso 8 to Lasso 9, and as an intermediate step, have upgraded from 8.5.5 to 8.6.2 (which runs alongside 9 on our new box, in different virtual hosts). I am finding that with 8.6.2 we are getting a slew of errors on pages that call encode_json. The weird thing with these errors is that they don't start happening until some period of time after the site starts. Then, some hours later, all encode_json calls begin to fail with error messages like this: An error occurred while processing your request. Error Information Error Message: No tag, type or constant was defined under the name "?????????????????" with arguments: array: (pair: (-find)=([\x{0020}-\x{21}\x{23}-\x{5b}\x{5d}-\x{10fff}])), (r) at: onCompare with params: 'r' at: JSON with params: 'reload', -Options=array: (-Internal) at: JSON with params: @map: (reload)=(false), (tcstring)=(LZU), (timestring)=(10:42 AM&nbsp;&nbsp;&nbsp;1442Z) at: [...].lasso with params: 'pageloadtime'='1383038310' on line: 31 at position: 1 Error Code: -9948 (Yes, those Chinese(?) characters are in the error message.) I have removed the 8.5.5 encode_json tag from LassoStartup, so we are using the correct built-in method. The encode_json method fails for any and all parameters I throw at it from simple strings to arrays of maps. Upon restarting the site, encode_json resumes working for an hour or two, seemingly depending on load. On 8.5.5, we don't have this problem. Does anyone have experience with this issue? Any advice regarding trying the 8.5.5 tag swap encode_json to see if I can override the built-in method? Maybe it will work better? Thanks in advance for your time and assistance. -Justin

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  • Extract information from a Func<bool, T> or alike lambda

    - by Syska
    I''m trying to build a generic cache layer. ICacheRepository Say I have the following: public class Person { public int PersonId { get; set; } public string Firstname { get; set; } public string Lastname { get; set; } public DateTime Added { get; set; } } And I have something like this: list.Where(x => x.Firstname == "Syska"); Here I want to extract the above information, to see if the query supplied the "PersonId" which it did not, so I dont want to cache it. But lets say I run a query like this: list.Where(x => x.PersonId == 10); Since PersonId is my key ... I want to cache it. with the key like "Person_10" and I later can fetch it from the cache. I know its possible to extract the information with Expression<Func<>> but there seems to be a big overhead of doing this (when running compile and extract the Constant values etc. and a bunch of cache to be sure to parse right) Are there a framework for this? Or some smart/golden way of doing this ?

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  • Maximize/Minimize is causing Close Button to be re-enabled after disabling it -- Why?

    - by Brainsick
    I have used P/Invoke to call GetSystemMenu and EnableMenuItem (win32api) to disable the close functionality. However, after minimizing or maximizing my Windows Forms application the button is re-enabled. Obviously minimizing or maximizing is causing the behavior, but how? I'm not sure where to look to prevent this behavior. Should I be preventing the maximize and minimize behavior or is there something particularly wrong with the way in which I P/Invoked the calls? Once the application (main form) has loaded, I call the static method from a button click. class PInvoke { // P/Invoke signatures [DllImport("user32.dll")] static extern IntPtr GetSystemMenu(IntPtr hWnd, bool bRevert); [DllImport("user32.dll")] static extern bool EnableMenuItem(IntPtr hMenu, uint uIDEnableItem, uint uEnable); // SysCommand (WM_SYSCOMMAND) constant internal const UInt32 SC_CLOSE = 0xF060; // Constants used with Add/Check/EnableMenuItem internal const UInt32 MF_BYCOMMAND = 0x00000000; internal const UInt32 MF_ENABLED = 0x00000000; internal const UInt32 MF_GRAYED = 0x00000001; internal const UInt32 MF_DISABLED = 0x00000002; /// <summary> /// Sets the state of the Close (X) button and the System Menu close functionality. /// </summary> /// <param name="window">Window or Form</param> /// <param name="bEnabled">Enabled state</param> public static void EnableCloseButton(IWin32Window window, bool bEnabled) { IntPtr hSystemMenu = GetSystemMenu(window.Handle, false); EnableMenuItem(hSystemMenu, SC_CLOSE, MF_BYCOMMAND | (bEnabled ? MF_ENABLED : MF_GRAYED)); } }

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  • Strange compilation error on reference passing argument to function

    - by Grewdrewgoo Goobergabbsoen
    Here's the code: #include <iostream> using namespace std; void mysize(int &size, int size2); int main() { int *p; int val; p = &val; cout << p; mysize(&val, 20); // Error is pointed here! } void mysize(int &size, int size2) { cout << sizeof(size); size2 = size2 + 6000; cout << size2; } Here's the error output from GCC: In function 'int main()': Line 10: error: invalid initialization of non-const reference of type 'int&' from a temporary of type 'int*' compilation terminated due to -Wfatal-errors. What does that imply? I do not understand the error message ... invalid initialization of a non-constant? I declared the prototype function above with two parameters to take, one a reference of an integer and one just an integer value itself. I passed the reference of the int (see line 10), yet this error keeps being thrown at me. What is the issue?

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  • Assign a static function to a variable in PHP

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

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  • What rules govern the copying of variables in Javascript closures?

    - by int3
    I'd just like to check my understanding of variable copying in Javascript. From what I gather, variables are passed/assigned by reference unless you explicitly tell them to create a copy with the new operator. But I'm a little uncertain when it comes to using closures. Say I have the following code: var myArray = [1, 5, 10, 15, 20]; var fnlist = []; for (var i in myArray) { var data = myArray[i]; fnlist.push(function() { var x = data; console.log(x); }); } fnlist[2](); // returns 20 I gather that this is because fnlist[2] only looks up the value of data at the point where it is invoked. So I tried an alternative tack: var myArray = [1, 5, 10, 15, 20]; var fnlist = []; for (var i in myArray) { var data = myArray[i]; fnlist.push(function() { var x = data; return function() { console.log(x); } }()); } fnlist[2](); // returns 10 So now it returns the 'correct' value. Am I right to say that it works because a function resolves all variable references to their 'constant' values when it is invoked? Or is there a better way to explain it? Any explanations / links to explanations regarding this referencing / copying business would be appreciated as well. Thanks!

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  • Storing C++ templated objects as same type

    - by JaredC
    I have a class that is a core component of a performance sensitive code path, so I am trying to optimize it as much as possible. The class used to be: class Widget { Widget(int n) : N(n) {} .... member functions that use the constant value N .... const int N; // just initialized, will never change } The arguments to the constructor are known at compile time, so I have changed this class to a template, so that N can be compiled into the functions: template<int N> class Widget { .... member functions that use N .... } I have another class with a method: Widget & GetWidget(int index); However, after templating Widget, each widget has a different type so I cannot define the function like this anymore. I considered different inheritance options, but I'm not sure that the performance gain from the template would outweigh the cost of inherited function invocations. SO, my question is this: I am pretty sure I want the best of both worlds (compile-time / run-time), and it may not be possible. But, is there a way to gain the performance of knowing N at compile time, but still being able to return Widgets as the same type? Thanks!

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  • Should I re-use UI elements across view controllers?

    - by Endemic
    In the iPhone app I'm currently working on, I'd like two navigation controllers (I'll call them A and B) to have toolbars that are identical in appearance and function. The toolbar in question will look like this: [(button) (flexible-space) (label)] For posterity's sake, the label is actually a UIBarButtonItem with a custom view. My design requires that A always appear directly before B on the navigation stack, so B will never be loaded without A having been loaded. Given this layout, I started wondering, "Is it worth it to re-use A's toolbar items in B's toolbar?" As I see it, my options are: 1. Don't worry about re-use, create the toolbar items twice 2. Create the toolbar items in A and pass them to B in a custom initializer 3. Use some more obscure method that I haven't thought of to hold the toolbar constant when pushing a view controller As far as I can see, option 1 may violate DRY, but guarantees that there won't be any confusion on the off chance that (for example) the button may be required to perform two different (no matter how similar) functions for either view controller in future versions of the app. Were that to happen, options 2 or 3 would require the target-action of the button to change when B is loaded and unloaded. Even if the button were never required to perform different functions, I'm not sure what its proper target would be under option 2. All in all, it's not a huge problem, even if I have to go with option 1. I'm probably overthinking this anyway, trying to apply the dependency injection pattern where it's not appropriate. I just want to know the best practice should this situation arise in a more extreme form, like if a long chain of view controllers need to use identical (in appearance and function) UI elements.

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  • OOP + MVC advice on Member Controller

    - by dan727
    Hi, I am trying to follow good practices as much as possible while I'm learning using OOP in an MVC structure, so i'm turning to you guys for a bit of advice on something which is bothering me a little here. I am writing a site where I will have a number of different forms for members to fill in (mainly data about themselves), so i've decided to set up a Member controller where all of the forms relating to the member are represented as individual methods. This includes login/logout methods, as well as editing profile data etc. In addition to these methods, i also have a method to generate the member's control panel widget, which is a constant on every page on the site while the member is logged in. The only thing is, all of the other methods in this controller all have the same dependencies and form templates, so it would be great to generate all this in the constructor, but as the control_panel method does not have the same dependencies etc, I cannot use the constructor for this purpose, and instead I have to redeclare the dependencies and same template snippets in each method. This obviously isn't ideal and doesn't follow DRY principle, but I'm wondering what I should do with the control_panel method, as it is related to the member and that's why I put it in that controller in the first place. Am I just over-complicating things here and does it make sense to just move the control_panel method into a simple helper class? Here are the basic methods of the controller: class Member_Controller extends Website_Controller { public function __construct() { parent::__construct(); if (request::is_ajax()) { $this->auto_render = FALSE; // disable auto render } } public static function control_panel() { //load control panel view $panel = new View('user/control_panel'); return $panel; } public function login() { } public function register() { } public function profile() { } public function household() { } public function edit_profile() { } public function logout() { } }

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  • PHP dynamic Page-level DocBlocks

    - by Obmerk Kronen
    I was wondering if there is a way to interact with the Page-level DocBlocks. My question is more specifically about wordpress plugin development, but this question has arised also in a non-wordpress environments. The reason is mainly the possibility to easily change VERSIONS and names throughout a large project with maybe a constant definition - but that will reflect also in the docblock.. The following example Docblock is from a wordpress plugin I write - /* Plugin Name: o99 Auxilary Functions v0.4.7 Plugin URI: http://www.myurl.com Description: some simple description that nobody reads. Version: 0.4.7 Author: my cool name Author URI: http://www.ok-alsouri.com */ Is there a way to transform it into : $ver = '0.4.7'; $uri = 'http://www.myurl.com'; $desc = 'some simple description that nobody reads.'; $mcn = 'my cool name'; etc.. etc.. /* Plugin Name: o99 Auxilary Functions ($ver) Plugin URI: ($uri) Description: ($desc) Version: ($ver) Author: ($mcn) Author URI: ($$uri) */ obviously for echo to work I would need to break the docblock itself, and I can not WRITE the docblock directly into it´s own file . In shorts : can I "generate" a docblock with php itself somehow (I would think that the answer is - "no" for the page itself.. But maybe I am wrong and someone has some neat hack :-) ) Is that even possible ?

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  • Update table instantly or “Bulk” Update in database later? And is it advisable?

    - by Mestika
    Hi, I have a question regarding a semi-constant update in a database. In short it is regarding a checkout function on a web page, which each time the checkout function is evoked it do five steps. I want to try to optimize this function and have my eye on a step where I update a table each time the checkout is performed. I take the information retrieved from the shopping cart and then update the table in question. I do have some indexes on the table, the gain from those are greater than leaving them so this is a cost I’m willing to take. Now, my question is. Could it in some way regarding to performance be better to not update the table instantly but collect every checkout items and save them in some way (maybe in a file) and then at a specific time (or several times) at day take this file and then update the table with the new information. Then I started thinking about if there was a possibility to use some sort of Bulk Update to take a file, hashmap, array (or?) and then update it. And I’m using IBM DB2 version 9.7 Mestika

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  • How to store and synchronize a big list of strings

    - by Joel
    I have a large database table in SQLExpress on Windows, with a particular field of interest 'code'. I have an Apache web server with MySQL on Linux. The web application on the Linux box needs access to the list of all codes. The only thing it will use the list for is checking for the existence of a given code. Having the Linux server call out to the Windows server is impractical as the Windows server is behind a NAT'ed office internet connection, and it may not always be accessible. I have set it so the Windows server will push the list of codes to the web server by means of a simple HTTP POST request. However, at this point I have not implemented the storage of the codes on the Linux box. Should I store them in a MySQL table with a single field 'code'? Then I get fast indexed lookups O(1), however I think synchronization will be an issue - given an updated list of codes, pushed from the Windows box, how would I optimally synchronize the list with the database? TRUNCATE, followed by INSERT? Should I instead store them in a flat file? Then I have O(n) look up time rather than O(1). Additionally an extra constant-time overhead too, as I will be processing the file in Ruby. However, synchronization is easy - simply replace the file.

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  • How to insert rows in a many-to-many relationship

    - by GSound
    Hello, I am having an issue trying to save into an intermediate table. I am new on Rails and I have spent a couple of hours on this but can't make it work, maybe I am doing wrong the whole thing. Any help will be appreciated. =) The app is a simple book store, where a logged-in user picks books and then create an order. This error is displayed: NameError in OrderController#create uninitialized constant Order::Orderlist These are my models: class Book < ActiveRecord::Base has_many :orderlists has_many :orders, :through => :orderlists end class Order < ActiveRecord::Base belongs_to :user has_many :orderlists has_many :books, :through => :orderlists end class OrderList < ActiveRecord::Base belongs_to :book belongs_to :order end This is my Order controller: class OrderController < ApplicationController def add if session[:user] book = Book.find(:first, :conditions => ["id = #{params[:id]}"]) if book session[:list].push(book) end redirect_to :controller => "book" else redirect_to :controller => "user" end end def create if session[:user] @order = Order.new if @order.save session[:list].each do |b| @order.orderlists.create(:book => b) # <-- here is my prob I cant make it work end end end redirect_to :controller => "book" end end Thnx in advance! Manuel

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  • Populate an Object Model from a data dataTable(C#3.0)

    - by Newbie
    I have a situation I am getting data from some external sources and is populating into the datatable. The data looks like this DATE WEEK FACTOR 3/26/2010 1 RM_GLOBAL_EQUITY 3/26/2010 1 RM_GLOBAL_GROWTH 3/26/2010 2 RM_GLOBAL_VALUE 3/26/2010 2 RM_GLOBAL_SIZE 3/26/2010 2 RM_GLOBAL_MOMENTUM 3/26/2010 3 RM_GLOBAL_HIST_BETA I have a object model like this public class FactorReturn { public int WeekNo { get; set; } public DateTime WeekDate { get; set; } public Dictionary<string, decimal> FactorCollection { get; set; } } As can be seen that the Date field is always constant. And a single(means unique) week can have multiple FACTORS. i.e. For a date(3/26/2010), for Week No. 1, there are two FACTORS(RM_GLOBAL_EQUITY and RM_GLOBAL_GROWTH). Similarly, For a date(3/26/2010), for Week No. 2, there are three FACTORS(RM_GLOBAL_VALUE , RM_GLOBAL_SIZE and RM_GLOBAL_MOMENTUM ). Now we need to populate this data into our object model. The final output will be WeekDate: 3/26/2010 WeekNo : 1 FactorCollection : RM_GLOBAL_EQUITY FactorCollection : RM_GLOBAL_GROWTH WeekNo : 2 FactorCollection : RM_GLOBAL_VALUE FactorCollection : RM_GLOBAL_SIZE FactorCollection : RM_GLOBAL_MOMENTUM WeekNo : 3 FactorCollection : RM_GLOBAL_HIST_BETA That is, overall only 1 single collection, where the Factor type will vary depending on week numbers. I have tried but of useless. Nothing works. Could you please help me?. I feel it is very tough I am using C# 3.0 Thanks

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  • how to change the image on click from database

    - by iosdev
    In my application i having multiple image in sq lite database,Since i want to change to the next image on button click,Here my code, -(void)Readthesqlitefile:(NSInteger *)sno { sqlite3 *database;//database object NSString *docpath=[self doccumentspath];//get sqlite path const char *ch=[docpath UTF8String];//string to constant char UTF8string main part to connect DB if (sqlite3_open(ch, &database)==SQLITE_OK) { const char *chstmt="SELECT * FROM animal where rowid= = %d",sno; sqlite3_stmt *sqlstmt;//to execute the above statement if (sqlite3_prepare_v2(database, chstmt, -1, &sqlstmt, NULL)==SQLITE_OK) { while (sqlite3_step(sqlstmt)==SQLITE_ROW) { const char *Bname=(char *)sqlite3_column_text(sqlstmt, 0); //converting const char to nsstring NSString *Bndname=[NSString stringWithFormat:@"%s",Bname]; NSLog(@"Brand Names=%@",Bndname); lb1.text=[NSString stringWithFormat:Bndname]; NSUInteger legnt=sqlite3_column_bytes(sqlstmt, 1); if (legnt>0) { NSData *dt=[NSData dataWithBytes:sqlite3_column_blob(sqlstmt, 1) length:legnt]; clsimg=[UIImage imageWithData:dt];//converting data to image imager.image=clsimg; } else { clsimg=nil; } } } sqlite3_finalize(sqlstmt); } sqlite3_close(database); } Button click function -(IBAction)changenext { int j; for (j=1; j<10; j++) { [self Readthesqlitefile:j]; } } its is not working pls help me to solve it out?

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  • determining the starting speed for an accelerated animation (in flash/actionscript but it's a math question)

    - by vulkanino
    This question burns my brain. I have an object on a plane, but for the sake of simplicity let's work just on a single dimension, thus the object has a starting position xs. I know the ending position xe. The object has to move from starting to ending position with an accelerated (acceleration=a) movement. I know the velocity the object has to have at the ending position (=ve). In my special case the ending speed is zero, but of course I need a general formula. The only unknown is the starting velocity vs. The objects starts with vs in xs and ends with ve in xe, moving along a space x with an acceleration a in a time t. Since I'm working with flash, space is expressed in pixels, time is expressed in frames (but you can reason in terms of seconds, it's easy to convert knowing the frames-per-second). In the animation loop (think onEnterFrame) I compute the new velocity and the new position with (a=0.4 for example): vx *= a (same for vy) x += vx (same for y) I want the entire animation to last, say, 2 seconds, which at 30 fps is 60 frames. Now you know that in 60 frames my object has to move from xs to xe with a constant deceleration so that the ending speed is 0. How do I compute the starting speed vs? Maybe there's a simpler way to do this in Flash, but I am now interested in the math/physics behind this.

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  • Travelling software. Is that a concept?

    - by Bubba88
    Hi! This is barely a sensible question. I would like to ask if there existed a program, which were intended to travel (for example following some physical forces) across the planet, possibly occupying and freeing computational resources/nodes. Literally that means that some agent-based system is just regularly changing it's location and (inevitably to some extent) configuration. An example would be: suppose you have external sensors, and free computers - nodes - across the space; would it make sense to self-replicate agents to follow the initializers from sensors, but in such restrictive manner that the computation is only localized at where the physical business is going on. I want to stress that this question is just for 'theoretical' fun, cause I cannot see any practical benefits of the restrictions mentioned, apart from the optimization of 'outdated' (outplaced?) agent disposal. But maybe it could be of some interest. Thank you! EDIT: It's obvious that a virus is fitting example, although the deletion of such agents is rarely of concern of the developers. More precisely, I'm interested in 'travelling' software - that is, when the count (or at least order) of the agents is kind of constant, and it's just the whole system who travels.

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  • C non-trivial constants

    - by user525869
    I want to make several constants in C with #define to speed up computation. Two of them are not simply trivial numbers, where one is a right shift, the other is a power. math.h in C gives the function pow() for doubles, whereas I need powers for integers, so I wrote my own function, ipow, so I wouldn't need to be casting everytime. My question is this: One of the #define constants I want to make is a power, say ipow(M, T), where M and T were also #define constants. ipow is a function in the actual code, so this actually seems to slows things down when I run the code (is it running ipow everytime the constant is mentioned?). However, when I ues the built in pow function and just do (int)pow(M,T), the code is sped up. I'm confused as to why this is, since the ipow and pow functions are just as fast. On a more general note, can I define constants using #define using functions inside the actual code? The above example has me confused on whether this speeds things up or actually slows things down.

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  • 'area' not declared in this scope

    - by user1641173
    I've just started learning c++ and am trying to write a program for finding the area of a circle. I've written the program and whenever I try to compile it I get 2 error messages. The first is: areaofcircle.cpp:9:14: error: expected unqualified-id before numeric constant and the second is: areaofcircle.cpp:18:5: error: 'area' was not declared in this scope What should I do? I would post a picture, but I'm a new user, so I can't. #include <iostream> using namespace std; #define pi 3.1415926535897932384626433832795 int main() { // Create three float variable values: r, pi, area float r, pi, area; cout << "This program computes the area of a circle." << endl; // Prompt user to enter the radius of the circle, read input value into variable r cout << "Enter the radius of the circle " << endl; cin >> r; // Square r and then multiply by pi area = r * r * pi; cout << "The area is " << area << "." << endl; }

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  • Can RPM packages be installed into Cygwin?

    - by Dejian Zhao
    I noticed that there is a command - rpm - under Cygwin 1.7. Does that mean RPM packages can be installed into Cygwin? I tried to install ncbi-blast-2.2.26+-3.i686.rpm (see: ftp://ftp.ncbi.nlm.nih.gov/blast/executables/blast+/LATEST/ ) into Cygwin 1.7.13 with the command "install -i ncbi-blast-2.2.26+-3.i686.rpm". However, error message appeared as below. I tried to search for the missing libs using the setup.exe of Cygwin. It seems that some of them were not present, such as libc.so.6, libdl.so.2, libm.so.6, libnsl.so.1, and libz.so.1. Where can I get these libs? Thanks! $ rpm -i ncbi-blast-2.2.26+-3.i686.rpm error: Failed dependencies: /usr/bin/perl is needed by ncbi-blast-2.2.26+-3 libbz2.so.1 is needed by ncbi-blast-2.2.26+-3 libc.so.6 is needed by ncbi-blast-2.2.26+-3 libc.so.6(GLIBC_2.0) is needed by ncbi-blast-2.2.26+-3 libc.so.6(GLIBC_2.1) is needed by ncbi-blast-2.2.26+-3 libc.so.6(GLIBC_2.1.2) is needed by ncbi-blast-2.2.26+-3 libc.so.6(GLIBC_2.1.3) is needed by ncbi-blast-2.2.26+-3 libc.so.6(GLIBC_2.2) is needed by ncbi-blast-2.2.26+-3 libc.so.6(GLIBC_2.3) is needed by ncbi-blast-2.2.26+-3 libdl.so.2 is needed by ncbi-blast-2.2.26+-3 libdl.so.2(GLIBC_2.0) is needed by ncbi-blast-2.2.26+-3 libdl.so.2(GLIBC_2.1) is needed by ncbi-blast-2.2.26+-3 libgcc_s.so.1 is needed by ncbi-blast-2.2.26+-3 libgcc_s.so.1(GCC_3.0) is needed by ncbi-blast-2.2.26+-3 libgcc_s.so.1(GLIBC_2.0) is needed by ncbi-blast-2.2.26+-3 libm.so.6 is needed by ncbi-blast-2.2.26+-3 libnsl.so.1 is needed by ncbi-blast-2.2.26+-3 libpthread.so.0 is needed by ncbi-blast-2.2.26+-3 libpthread.so.0(GLIBC_2.0) is needed by ncbi-blast-2.2.26+-3 libpthread.so.0(GLIBC_2.1) is needed by ncbi-blast-2.2.26+-3 libpthread.so.0(GLIBC_2.2) is needed by ncbi-blast-2.2.26+-3 libpthread.so.0(GLIBC_2.3.2) is needed by ncbi-blast-2.2.26+-3 librt.so.1 is needed by ncbi-blast-2.2.26+-3 libstdc++.so.6 is needed by ncbi-blast-2.2.26+-3 libstdc++.so.6(CXXABI_1.3) is needed by ncbi-blast-2.2.26+-3 libstdc++.so.6(GLIBCXX_3.4) is needed by ncbi-blast-2.2.26+-3 libstdc++.so.6(GLIBCXX_3.4.5) is needed by ncbi-blast-2.2.26+-3 libz.so.1 is needed by ncbi-blast-2.2.26+-3 perl(Archive::Tar) is needed by ncbi-blast-2.2.26+-3 perl(Digest::MD5) is needed by ncbi-blast-2.2.26+-3 perl(File::Temp) is needed by ncbi-blast-2.2.26+-3 perl(File::stat) is needed by ncbi-blast-2.2.26+-3 perl(Getopt::Long) is needed by ncbi-blast-2.2.26+-3 perl(Net::FTP) is needed by ncbi-blast-2.2.26+-3 perl(Pod::Usage) is needed by ncbi-blast-2.2.26+-3 perl(constant) is needed by ncbi-blast-2.2.26+-3 perl(strict) is needed by ncbi-blast-2.2.26+-3 perl(warnings) is needed by ncbi-blast-2.2.26+-3

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