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  • How is it possible the class inheritance in namespaces using Ruby on Rails 3?

    - by user502052
    In my RoR3 application I have a namespace called NS1 so that I have this filesystem structure: ROOT_RAILS/controllers/ ROOT_RAILS/controllers/application_controller.rb ROOT_RAILS/controllers/ns/ ROOT_RAILS/controllers/ns/ns_controller.rb ROOT_RAILS/controllers/ns/names_controller.rb ROOT_RAILS/controllers/ns/surnames_controller.rb I wuold like that 'ns_controller.rb' inherits from application controller, so in 'ns_controller.rb' file I have: class Ns::NsController < ApplicationController ... end Is this the right approach? Anyway if I have this situation... in 'application_controller.rb' class ApplicationController < ActionController::Base @profile = Profile.find(1) end in 'ns_controller.rb' class Ns::NsController < ApplicationController @name = @profile.name @surname = @profile.surname end ... '@name' and '@surname' variables are not set. Why?

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  • a nicer way to create structs in a loop

    - by sandra
    Hi guys, I haven't coded in C++ in ages. And recently, I'm trying to work on something involving structs. Like this typedef struct{ int x; int y; } Point; Then in a loop, I'm trying to create new structs and put pointers to them them in a list. Point* p; int i, j; while (condition){ // compute values for i and j with some function... p = new Point; p* = {i, j}; //initialize my struct. list.append(p); //append this pointer to my list. } Now, my question is it possible to simplify this? I mean, the pointer variable *p outside of the loop and calling p = new Point inside the loop. Isn't there a better/nicer syntax for this?

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  • Can someone explain how pointer to pointer works?

    - by user3549560
    I don't really understand how the pointer to pointer works. Any way to do the same work without using pointer to pointer? struct customer{ char name[20]; char surname[20]; int code; float money; }; typedef struct customer customer; void inserts(customer **tmp) { *tmp = (customer*)malloc(sizeof(customer)); puts("Give me a customer name, surname code and money"); scanf("%s %s %d %f", (*tmp)->name, (*tmp)->surname, &(*tmp)->code,&(*tmp)->money); }

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  • C Structure Pointer Problem

    - by Halo
    I have this struct; #define BUFSIZE 10 struct shared_data { pthread_mutex_t th_mutex_queue; int count; int data_buffer_allocation[BUFSIZE]; int data_buffers[BUFSIZE][100]; }; and I want to allocate one of the data_buffers for a process, for that purpose I execute the following function; int allocate_data_buffer(int pid) { int i; for (i = 0; i < BUFSIZE; i++) { if (sdata_ptr->data_buffer_allocation[i] == NULL) { sdata_ptr->data_buffer_allocation[i] = pid; return i; } } return -1; } but the compiler warns me that I'm comparing pointer to a value. When I put a & in front of sdata_ptr it calms down but I'm not sure if it will work. Isn't what I wrote above supposed to be true?

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  • Can I set a PHP class property from an existing variable?

    - by jasondavis
    I am trying to figure out how I want to handle settings in my PHP app. I have pretty much decide that I would like to use a Confg class file so it will be autoloaded and flexible in the future. Below is some stuff I was playing with. I know you cannot set a variable to popluate a Constant so I then try to use a public static property. Why can I not set public static $ip = $_SERVER['REMOTE_ADDR']; ?? <?php // config.class.php class Config { const URL = 'http://www.foo.com'; const DB_User = 'dbname'; public static $test = 'test string'; public static $ip = $_SERVER['REMOTE_ADDR']; } /////////////////////////////////////////////////////// //index.php // works echo Config::URL; // works echo Config::$test; // DOES NOT WORK echo Config::$ip; ?>

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  • Enterprise Library Validation Block - Should validation be placed on class or interface?

    - by Robert MacLean
    I am not sure where the best place to put validation (using the Enterprise Library Validation Block) is? Should it be on the class or on the interface? Things that may effect it Validation rules would not be changed in classes which inherit from the interface. Validation rules would not be changed in classes which inherit from the class. Inheritance will occur from the class in most cases - I suspect some fringe cases to inherit from the interface (but I would try and avoid it). The interface main use is for DI which will be done with the Unity block.

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  • What's wrong with consuming ConfiguredTaskAwaitable from PortableClassLibrary's class under Debugger from MSTest Runner or Console App?

    - by Stas Shusha
    *Its only Debug-time error, but a very weird one. Problem: While running with Debugger attached and calling a method, exposed in separate Portable library, returning ConfiguredTaskAwaitable, we get InvalidProgramException. Repro: Having 2 projects: PortableClassLibrary (supporting .Net 4.5; Windows Store; Windows Phone 8) with 1 class: public class Weird { public static ConfiguredTaskAwaitable GetConfiguredTaskAwaitable() { return new ConfiguredTaskAwaitable(); } } ConsoleApplication with code: static void Main(string[] args) { Weird.GetConfiguredTaskAwaitable(); } Notes: replacing ConfiguredTaskAwaitable with ConfiguredTaskAwaitable<T> (a generic version) fixes this strange issue consuming this method form WP8 or Win8 app under Debugger works fine. Currently it causes problems cause I cant run my Unit Tests under Debugger. I'm forced to change my "ObjectUnderTest" implementation to return generic ConfiguredTaskAwaitable<T>, which is fine for the real project, but still is only a workaround. The Question is: does anybody knows the reason of this error? It definitely related to Portable Class Library magic.

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  • How can a class's memory-allocated address be determined from within the contructor?

    - by Jim Fell
    Is it possible to get the memory-allocated address of a newly instantiated class from within that class's constructor during execution of said constructor? I am developing a linked list wherein multiple classes have multiple pointers to like classes. Each time a new class instantiates, it needs to check its parent's list to make sure it is included. If I try to do something like this: MyClass() // contructor { extern MyClass * pParent; for ( int i = 0; i < max; i++ ) { pParent->rels[i] == &MyClass; // error } } I get this error: error C2275: 'namespace::MyClass' : illegal use of this type as an expression Any thoughts or suggestions would be appreciated. Thanks.

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  • Overloading Console.ReadLine possible? (or any static class method)

    - by comecme
    I'm trying to create an overload of the System.Console.ReadLine() method that will take a string argument. My intention basically is to be able to write string s = Console.ReadLine("Please enter a number: "); in stead of Console.Write("Please enter a number: "); string s = Console.ReadLine(); I don't think it is possible to overload Console.ReadLine itself, so I tried implementing an inherited class, like this: public static class MyConsole : System.Console { public static string ReadLine(string s) { Write(s); return ReadLine(); } } That doesn't work though, cause it is not possible to inherit from System.Console (because it is a static class which automatically makes is a sealed class). Does it make sense what I'm trying to do here? Or is it never a good idea to want to overload something from a static class?

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  • Attach an HREF and a class to an img link generated by the PhotoSlider script?

    - by Frank Bailey
    Hi folks, I'm using the very nice PhotoSlider script from http://opiefoto.com/articles/photoslider to create a slide show of images for one of my clients. This script replaces a previous hand-coded Javascript solution that allowed for the large image to be clicked resulting in a lightbox modal popup showing the full-size version of the clicked picture. Of course the client insists that this functionality remain intact, but the HTML code for the large image is generated on-the-fly by the PhotoSlider script itself. This means I'll need to modify the script slightly to attach a class ("lightbox") and an href (or just a click event, whichever makes more sense), but I'm not quite sure how best to accomplish this. I figure the event and class will have to be attached each time a thumbnail is clicked, but if this isn't the best way to do it any advice will be appreciated. The script is implemented into my page as can be seen here, without the click or class. I'd really appreciate any assistance stackoverflowites can offer. Thanks in advance!

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  • design function: underlying structure to store list of results for print to file

    - by forest.peterson
    is this a good approach to print a list of items to csv file with a sublist attached to each item. The gist of the function is when an item is found that does not exactly macth then a list of close matches is generated - this works now writing out one list at a time to a command window. For export to a csv file I think all the lists must be generated, stored and then written at once. Right now I use a struct to store the attributes printed, each struct is an item on the list - these structs are then added to a sorted stack and when printed they pop off into write out. Is a stack of stacks of structs a good design?

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  • Can I use string concatenation to define a class CONST in PHP?

    - by selfsimilar
    I know that you can create global constants in terms of each other using string concatenation: define('FOO', 'foo'); define('BAR', FOO.'bar'); echo BAR; will print 'foobar'. However, I'm getting an error trying to do the same using class constants. class foobar { const foo = 'foo'; const foo2 = self::foo; const bar = self::foo.'bar'; } foo2 is defined without issue, but declaring const bar will error out Parse error: syntax error, unexpected '.', expecting ',' or ';' I've also tried using functions like sprintf() but it doesn't like the left paren any more than the string concatenator '.'. So is there any way to create class constants in terms of each other in anything more than a trivial set case like foo2?

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  • How to access CWebBrowser class instance (defined in a protected class) in a different class? C++

    - by extintor
    I have been playing with this webbrowser control example I got it working and added some timers using ON_WM_TIMER. Now I would like to access the m_Browser (CWebBrowser class instance) defined inside the protected CMyBrowserView class into a different class. (for example CMyBrowserApp in the code sample) and use .Navigate and other functions. How can I do this? (im using visual studio 6 c++)

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  • What's safe to assume about the NSMutableArray / NSArray class cluster?

    - by andyvn22
    I know you shouldn't use this to decide whether or not to change an array: if ([possiblyMutable isKindOfClass:[NSMutableArray class]]) But say I'm writing a method and need to return either an NSMutableArray or an NSArray, depending on the mutability of possiblyMutable. The class using my method already knows whether or not it's acceptable to change the returned array. Whether or not it's acceptable to change the returned array directly correlates with whether or not it's acceptable to change possiblyMutable. In that specific case, is this code safe? It seems to me that if it's not acceptable to change the array, but we accidentally get a mutable array, it's ok, because the class using my method won't try to change it. And if it is acceptable to change the array, then we will always get possiblyMutable as an NSMutableArray (though this is the part I'm not entirely clear on). So... safe or not? Alternatives?

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  • How do I ensure my abstract class's function can only operate on extenders of the same type as the c

    - by incrediman
    For example, let's say this is my abstract class: abstract class A{ int x; int y; void foo(A fooMe); } ...and B and C are two classes which extend A. What I want is for B to only be able to call foo() on other Bs, and for C to only be able to call foo() on other Cs. But I want this to be out of the hands of the programmer who's extending my A class - that is, I want a way to ensure this functionality within As code alone. What can I do? (If possible) I'd like to avoid any hack or generics solution that's too messy - I still want foo to be able to be called like this, for example: B b=new B(); B bb=new B(); bb.foo(b);

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  • 'array bound is not an integer constant' when defining size of array in class, using an element of a const array

    - by user574733
    #ifndef QWERT_H #define QWERT_H const int x [] = {1, 2,}; const int z = 3; #endif #include <iostream> #include "qwert.h" class Class { int y [x[0]]; //error:array bound is not an integer constant int g [z]; //no problem }; int main () { int y [x[0]]; //no problem Class a_class; } I can't figure out why this doesn't work. Other people with this problem seem to be trying to dynamically allocate arrays. Any help is much appreciated.

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  • How to define a new type (class) in Python using C API?

    - by ~mech
    Hi, I am trying to use the Python C API to define a new class inside a module that would expose certain functionality written in C to Python code. I specifically want to have it in the form of a class and not a set of module functions. However, I can't find anything regarding this particular task in the official documentation. The closest I could find is PyClass_New function (in the Python.h header) but it is not mentioned anywhere in the official docs, so I assume it is not supposed to be used. So, what is the proper way to define a new Python class from C code? Thanks.

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  • Stucture with array of pointers in C

    - by MVTCplusplus
    What's wrong with this? Can I have an array of pointers to SDL_Surfaces in a struct in C? typedef struct { int next_wheel; int pos_X; int pos_Y; int front_wheel_pos_X; int front_wheel_pos_Y; int velocity; int rear_wheel_pos_X; int rear_wheel_pos_Y; SDL_Surface* body; SDL_Surface* rear_wheel[9]; SDL_Surface* front_wheel[9]; } mars_rover; ... mars_rover* init_rover() { mars_rover* rover = (mars_rover*)malloc(sizeof(mars_rover) + sizeof(SDL_Surface) * 19); ... return rover; } int main() { mars_rover* rover = init_rover(); ... }

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  • Structs and pointers

    - by user1763861
    I have a few questions about structs and pointers For this struct: typedef struct tNode_t { char *w; } tNode; How come if I want to change/know the value of *w I need to use t.w = "asdfsd" instead of t->w = "asdfasd"? And I compiled this successfully without having t.w = (char *) malloc(28*sizeof(char)); in my testing code, is there a reason why tt's not needed? Sample main: int main() { tNode t; char w[] = "abcd"; //t.word = (char *) malloc(28*sizeof(char)); t.word = w; printf("%s", t.word); } Thanks.

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  • C - How to manipulate typedef structure pointer?

    - by AbhishekJoshi
    typedef struct { int id; char* first; char* last; }* person; person* people; Hi. How can I use this above, all set globally, to fill people with different "person"s? I am having issues wrapping my head regarding the typedef struct pointer. I am aware pointers are like arrays, but I'm having issues getting this all together... I would like to keep the above code as is as well. Edit 1: char first should be char* first.

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  • Using the StopWatch class to calculate the execution time of a block of code

    - by vik20000in
      Many of the times while doing the performance tuning of some, class, webpage, component, control etc. we first measure the current time taken in the execution of that code. This helps in understanding the location in code which is actually causing the performance issue and also help in measuring the amount of improvement by making the changes. This measurement is very important as it helps us understand the problem in code, Helps us to write better code next time (as we have already learnt what kind of improvement can be made with different code) . Normally developers create 2 objects of the DateTime class. The exact time is collected before and after the code where the performance needs to be measured.  Next the difference between the two objects is used to know about the time spent in the code that is measured. Below is an example of the sample code.             DateTime dt1, dt2;             dt1 = DateTime.Now;             for (int i = 0; i < 1000000; i++)             {                 string str = "string";             }             dt2 = DateTime.Now;             TimeSpan ts = dt2.Subtract(dt1);             Console.WriteLine("Time Spent : " + ts.TotalMilliseconds.ToString());   The above code works great. But the dot net framework also provides for another way to capture the time spent on the code without doing much effort (creating 2 datetime object, timespan object etc..). We can use the inbuilt StopWatch class to get the exact time spent. Below is an example of the same work with the help of the StopWatch class.             Stopwatch sw = Stopwatch.StartNew();             for (int i = 0; i < 1000000; i++)             {                 string str = "string";             }             sw.Stop();             Console.WriteLine("Time Spent : " +sw.Elapsed.TotalMilliseconds.ToString());   [Note the StopWatch class resides in the System.Diagnostics namespace] If you use the StopWatch class the time taken for measuring the performance is much better, with very little effort. Vikram

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  • Data classes: getters and setters or different method design

    - by Frog
    I've been trying to design an interface for a data class I'm writing. This class stores styles for characters, for example whether the character is bold, italic or underlined. But also the font-size and the font-family. So it has different types of member variables. The easiest way to implement this would be to add getters and setters for every member variable, but this just feels wrong to me. It feels way more logical (and more OOP) to call style.format(BOLD, true) instead of style.setBold(true). So to use logical methods insteads of getters/setters. But I am facing two problems while implementing these methods: I would need a big switch statement with all member variables, since you can't access a variable by the contents of a string in C++. Moreover, you can't overload by return type, which means you can't write one getter like style.getFormatting(BOLD) (I know there are some tricks to do this, but these don't allow for parameters, which I would obviously need). However, if I would implement getters and setters, there are also issues. I would have to duplicate quite some code because styles can also have a parent styles, which means the getters have to look not only at the member variables of this style, but also at the variables of the parent styles. Because I wasn't able to figure out how to do this, I decided to ask a question a couple of weeks ago. See Object Oriented Programming: getters/setters or logical names. But in that question I didn't stress it would be just a data object and that I'm not making a text rendering engine, which was the reason one of the people that answered suggested I ask another question while making that clear (because his solution, the decorator pattern, isn't suitable for my problem). So please note that I'm not creating my own text rendering engine, I just use these classes to store data. Because I still haven't been able to find a solution to this problem I'd like to ask this question again: how would you design a styles class like this? And why would you do that? Thanks on forehand!

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  • Is this the correct approach to an OOP design structure in php?

    - by Silver89
    I'm converting a procedural based site to an OOP design to allow more easily manageable code in the future and so far have created the following structure: /classes /templates index.php With these classes: ConnectDB Games System User User -Moderator User -Administrator In the index.php file I have code that detects if any $_GET values are posted to determine on which page content to build (it's early so there's only one example and no default): function __autoload($className) { require "classes/".strtolower($className).".class.php"; } $db = new Connect; $db->connect(); $user = new User(); if(isset($_GET['gameId'])) { System::buildGame($gameId); } This then runs the BuildGame function in the system class which looks like the following and then uses gets in the Game Class to return values, such as $game->getTitle() in the template file template/play.php: function buildGame($gameId){ $game = new Game($gameId); $game->setRatio(900, 600); require 'templates/play.php'; } I also have .htaccess so that actual game page url works instead of passing the parameters to index.php Are there any major errors of how I'm setting this up or do I have the general idea of OOP correct?

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