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  • which style of member-access is preferable

    - by itwasntpete
    the purpose of oop using classes is to encapsulate members from the outer space. i always read that accessing members should be done by methods. for example: template<typename T> class foo_1 { T state_; public: // following below }; the most common doing that by my professor was to have a get and set method. // variant 1 T const& getState() { return state_; } void setState(T const& v) { state_ = v; } or like this: // variant 2 // in my opinion it is easier to read T const& state() { return state_; } void state(T const& v) { state_ = v; } assume the state_ is a variable, which is checked periodically and there is no need to ensure the value (state) is consistent. Is there any disadvantage of accessing the state by reference? for example: // variant 3 // do it by reference T& state() { return state_; } or even directly, if I declare the variable as public. template<typename T> class foo { public: // variant 4 T state; }; In variant 4 I could even ensure consistence by using c++11 atomic. So my question is, which one should I prefer?, Is there any coding standard which would decline one of these pattern? for some code see here

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  • Why am I seeing so many instantiable classes without state?

    - by futlib
    I'm seeing a lot of instantiable classes in the C++ and Java world that don't have any state. I really can't figure out why people do that, they could just use a namespace with free functions in C++, or a class with a private constructor and only static methods in Java. The only benefit I can think of is that you don't have to change most of your code if you later decide that you want a different implementation in certain situations. But isn't that a case of premature design? It could be turned into a class later, when/if it becomes appropriate. Am I getting this wrong? Is it not OOP if I don't put everything into objects (i.e. instantiated classes)? Then why are there so many utility namespaces and classes in the standard libraries of C++ and Java? Update: I've certainly seen a lot examples of this in my previous jobs, but I'm struggling to find open source examples, so maybe it's not that common after all. Still, I'm wondering why people do it, and how common it is.

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  • Passing variables, creating instances, self, The mechanics and usage of classes: need explenation

    - by Baf
    I've been sitting over this the whole day and Im a little tired already so please excuse me being brief. Im new to python. I just rewrrote a working program, into a bunch of functions in a class and everzthings messed up. I dont know if its me but Im very surprised i couldn t find a beginners tutorial on how to handle classes on the web so I have a few questions. First of all, in the init section of the class i have declared a bunch of variables with self.variable=something. Is it correct that i should be able to access/modify these variables in every function of the class by using self.variable in that function? In other words by declaring self.variable i have made these variables, global variables in the scope of the class right? If not how do i handle self. ? Secondly how do i correctly pass arguments to the class? some example code would be cool. thirdly how do i call a function of the class outside of the class scope? some example code would be cool. fouthly how do I create an Instance of the class INITIALCLASS in another class OTHERCLASS, passing variables from OTHERCLASS to INITIALCLASS? some example code would be cool. I Want to call a function from OTHERCLASS with arguments from INITIALCLASS. What Ive done so far is. class OTHERCLASS(): def __init__(self,variable1,variable2,variable3): self.variable1=variable1 self.variable2=variable2 self.variable3=variable3 def someotherfunction(self): something=somecode(using self.variable3) self.variable2.append(something) print self.variable2 def somemorefunctions(self): self.variable2.append(variable1) class INITIALCLASS(): def __init__(self): self.variable1=value1 self.variable2=[] self.variable3='' self.DoIt=OTHERCLASS(variable1,variable2,variable3) def somefunction(self): variable3=Somecode #tried this self.DoIt.someotherfunctions() #and this DoIt.someotherfunctions() I clearly havent understood how to pass variables to classes or how to handle self, when to use it and when not, I probably also havent understood how to properly create an isntance of a class. In general i havent udnerstood the mechanics of classes So please help me and explain it to me like i have no Idea( which i dont it seems). Or point me to a thorough video, or readable tutorial. All i find on the web is super simple examples, that didnt help me much. Or just very short definitions of classes and class methods instances etc. I can send you my original code if you guys want, but its quite long. Thanks for the Help Much appreciated!

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  • JavaScript Class Patterns

    - by Liam McLennan
    To write object-oriented programs we need objects, and likely lots of them. JavaScript makes it easy to create objects: var liam = { name: "Liam", age: Number.MAX_VALUE }; But JavaScript does not provide an easy way to create similar objects. Most object-oriented languages include the idea of a class, which is a template for creating objects of the same type. From one class many similar objects can be instantiated. Many patterns have been proposed to address the absence of a class concept in JavaScript. This post will compare and contrast the most significant of them. Simple Constructor Functions Classes may be missing but JavaScript does support special constructor functions. By prefixing a call to a constructor function with the ‘new’ keyword we can tell the JavaScript runtime that we want the function to behave like a constructor and instantiate a new object containing the members defined by that function. Within a constructor function the ‘this’ keyword references the new object being created -  so a basic constructor function might be: function Person(name, age) { this.name = name; this.age = age; this.toString = function() { return this.name + " is " + age + " years old."; }; } var john = new Person("John Galt", 50); console.log(john.toString()); Note that by convention the name of a constructor function is always written in Pascal Case (the first letter of each word is capital). This is to distinguish between constructor functions and other functions. It is important that constructor functions be called with the ‘new’ keyword and that not constructor functions are not. There are two problems with the pattern constructor function pattern shown above: It makes inheritance difficult The toString() function is redefined for each new object created by the Person constructor. This is sub-optimal because the function should be shared between all of the instances of the Person type. Constructor Functions with a Prototype JavaScript functions have a special property called prototype. When an object is created by calling a JavaScript constructor all of the properties of the constructor’s prototype become available to the new object. In this way many Person objects can be created that can access the same prototype. An improved version of the above example can be written: function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { toString: function() { return this.name + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); In this version a single instance of the toString() function will now be shared between all Person objects. Private Members The short version is: there aren’t any. If a variable is defined, with the var keyword, within the constructor function then its scope is that function. Other functions defined within the constructor function will be able to access the private variable, but anything defined outside the constructor (such as functions on the prototype property) won’t have access to the private variable. Any variables defined on the constructor are automatically public. Some people solve this problem by prefixing properties with an underscore and then not calling those properties by convention. function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { _getName: function() { return this.name; }, toString: function() { return this._getName() + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); Note that the _getName() function is only private by convention – it is in fact a public function. Functional Object Construction Because of the weirdness involved in using constructor functions some JavaScript developers prefer to eschew them completely. They theorize that it is better to work with JavaScript’s functional nature than to try and force it to behave like a traditional class-oriented language. When using the functional approach objects are created by returning them from a factory function. An excellent side effect of this pattern is that variables defined with the factory function are accessible to the new object (due to closure) but are inaccessible from anywhere else. The Person example implemented using the functional object construction pattern is: var personFactory = function(name, age) { var privateVar = 7; return { toString: function() { return name + " is " + age * privateVar / privateVar + " years old."; } }; }; var john2 = personFactory("John Lennon", 40); console.log(john2.toString()); Note that the ‘new’ keyword is not used for this pattern, and that the toString() function has access to the name, age and privateVar variables because of closure. This pattern can be extended to provide inheritance and, unlike the constructor function pattern, it supports private variables. However, when working with JavaScript code bases you will find that the constructor function is more common – probably because it is a better approximation of mainstream class oriented languages like C# and Java. Inheritance Both of the above patterns can support inheritance but for now, favour composition over inheritance. Summary When JavaScript code exceeds simple browser automation object orientation can provide a powerful paradigm for controlling complexity. Both of the patterns presented in this article work – the choice is a matter of style. Only one question still remains; who is John Galt?

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  • JavaScript Class Patterns

    - by Liam McLennan
    To write object-oriented programs we need objects, and likely lots of them. JavaScript makes it easy to create objects: var liam = { name: "Liam", age: Number.MAX_VALUE }; But JavaScript does not provide an easy way to create similar objects. Most object-oriented languages include the idea of a class, which is a template for creating objects of the same type. From one class many similar objects can be instantiated. Many patterns have been proposed to address the absence of a class concept in JavaScript. This post will compare and contrast the most significant of them. Simple Constructor Functions Classes may be missing but JavaScript does support special constructor functions. By prefixing a call to a constructor function with the ‘new’ keyword we can tell the JavaScript runtime that we want the function to behave like a constructor and instantiate a new object containing the members defined by that function. Within a constructor function the ‘this’ keyword references the new object being created -  so a basic constructor function might be: function Person(name, age) { this.name = name; this.age = age; this.toString = function() { return this.name + " is " + age + " years old."; }; } var john = new Person("John Galt", 50); console.log(john.toString()); Note that by convention the name of a constructor function is always written in Pascal Case (the first letter of each word is capital). This is to distinguish between constructor functions and other functions. It is important that constructor functions be called with the ‘new’ keyword and that not constructor functions are not. There are two problems with the pattern constructor function pattern shown above: It makes inheritance difficult The toString() function is redefined for each new object created by the Person constructor. This is sub-optimal because the function should be shared between all of the instances of the Person type. Constructor Functions with a Prototype JavaScript functions have a special property called prototype. When an object is created by calling a JavaScript constructor all of the properties of the constructor’s prototype become available to the new object. In this way many Person objects can be created that can access the same prototype. An improved version of the above example can be written: function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { toString: function() { return this.name + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); In this version a single instance of the toString() function will now be shared between all Person objects. Private Members The short version is: there aren’t any. If a variable is defined, with the var keyword, within the constructor function then its scope is that function. Other functions defined within the constructor function will be able to access the private variable, but anything defined outside the constructor (such as functions on the prototype property) won’t have access to the private variable. Any variables defined on the constructor are automatically public. Some people solve this problem by prefixing properties with an underscore and then not calling those properties by convention. function Person(name, age) { this.name = name; this.age = age; } Person.prototype = { _getName: function() { return this.name; }, toString: function() { return this._getName() + " is " + this.age + " years old."; } }; var john = new Person("John Galt", 50); console.log(john.toString()); Note that the _getName() function is only private by convention – it is in fact a public function. Functional Object Construction Because of the weirdness involved in using constructor functions some JavaScript developers prefer to eschew them completely. They theorize that it is better to work with JavaScript’s functional nature than to try and force it to behave like a traditional class-oriented language. When using the functional approach objects are created by returning them from a factory function. An excellent side effect of this pattern is that variables defined with the factory function are accessible to the new object (due to closure) but are inaccessible from anywhere else. The Person example implemented using the functional object construction pattern is: var john = new Person("John Galt", 50); console.log(john.toString()); var personFactory = function(name, age) { var privateVar = 7; return { toString: function() { return name + " is " + age * privateVar / privateVar + " years old."; } }; }; var john2 = personFactory("John Lennon", 40); console.log(john2.toString()); Note that the ‘new’ keyword is not used for this pattern, and that the toString() function has access to the name, age and privateVar variables because of closure. This pattern can be extended to provide inheritance and, unlike the constructor function pattern, it supports private variables. However, when working with JavaScript code bases you will find that the constructor function is more common – probably because it is a better approximation of mainstream class oriented languages like C# and Java. Inheritance Both of the above patterns can support inheritance but for now, favour composition over inheritance. Summary When JavaScript code exceeds simple browser automation object orientation can provide a powerful paradigm for controlling complexity. Both of the patterns presented in this article work – the choice is a matter of style. Only one question still remains; who is John Galt?

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  • The Excel Column Name assigment problem

    - by Peter Larsson
    Here is a generic algorithm to get the Excel column name according to it's position. By changing the @Base parameter, you can do this for any sequence according to same style as Excel. DECLARE @Value INT = 8839,         @Base TINYINT = 26   ;WITH cteSequence(Value, Delta, Quote, Base, Chr) AS (     SELECT  CAST(@Value AS INT) AS Value,             CAST(1 AS INT) AS Delta,             CAST(@Base AS INT) AS Quote,             CAST(@Base AS INT) AS Base,             CHAR(65 +(@Value - 1) % @Base) AS Chr       UNION ALL       SELECT  Value AS Value,             Quote AS Delta,             26 * Quote AS Quote,             Base AS Base,             CHAR(65 +((Value - Delta)/ Quote - 1) % Base) AS Chr     FROM    cteSequence     WHERE   CHAR(65 +((Value - Delta)/ Quote - 1) % Base) <> '@' ) SELECT  CAST(Msg AS VARCHAR(MAX)) FROM    (             SELECT        '' + Chr             FROM        cteSequence             ORDER BY    Delta DESC             FOR XML        PATH('')         ) AS x(Msg)

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  • CA2000 passing object reference to base constructor in C#

    - by Timothy
    I receive a warning when I run some code through Visual Studio's Code Analysis utility which I'm not sure how to resolve. Perhaps someone here has come across a similar issue, resolved it, and is willing to share their insight. I'm programming a custom-painted cell used in a DataGridView control. The code resembles: public class DataGridViewMyCustomColumn : DataGridViewColumn { public DataGridViewMyCustomColumn() : base(new DataGridViewMyCustomCell()) { } It generates the following warning: CA2000 : Microsoft.Reliability : In method 'DataGridViewMyCustomColumn.DataGridViewMyCustomColumn()' call System.IDisposable.Dispose on object 'new DataGridViewMyCustomCell()' before all references to it are out of scope. I understand it is warning me DataGridViewMyCustomCell (or a class that it inherits from) implements the IDisposable interface and the Dispose() method should be called to clean up any resources claimed by DataGridViewMyCustomCell when it is no longer. The examples I've seen on the internet suggest a using block to scope the lifetime of the object and have the system automatically dispose it, but base isn't recognized when moved into the body of the constructor so I can't write a using block around it... which I'm not sure I'd want to do anyway, since wouldn't that instruct the run time to free the object which could still be used later inside the base class? My question then, is the code okay as is? Or, how could it be refactored to resolve the warning? I don't want to suppress the warning unless it is truly appropriate to do so.

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  • Storing class constants (for use as bitmask) in a database?

    - by fireeyedboy
    Let's say I have a class called Medium which can represent different types of media. For instance: uploaded video embedded video uploaded image embedded image I represent these types with contants, like this: class MediumAbstract { const UPLOAD = 0x0001; const EMBED = 0x0010; const VIDEO = 0x0100; const IMAGE = 0x1000; const VIDEO_UPLOAD = 0x0101; // for convenience const VIDEO_EMBED = 0x0110; // for convenience const IMAGE_UPLOAD = 0x1001; // for convenience const IMAGE_EMBED = 0x1010; // for convenience const ALL = 0x1111; // for convenience } Thus, it is easy for me to do a combined search on them on an (abstract) repository, with something like: { public function findAllByType( $type ) { ... } } $media = $repo->findAllByType( MediumAbstract::VIDEO | MediumAbstract::IMAGE_UPLOAD ); // or $media = $repo->findAllByType( MediumAbstract::ALL ); // etc.. How do you feel about using these constant values in a concrete repository like a database? Is it ok? Or should I substitute them with meaningful data in the database. Table medium: | id | type | location | etc.. ------------------------------------------------- | 1 | use constants here? | /some/path | etc.. (Of course I'll only be using the meaningful constants: VIDEO_UPLOAD, VIDEO_EMBED, IMAGE_UPLOAD and IMAGE_EMBED)

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  • Ambiguous access to base class template member function

    - by Johann Gerell
    In Visual Studio 2008, the compiler cannot resolve the call to SetCustomer in _tmain below and make it unambiguous: template <typename TConsumer> struct Producer { void SetConsumer(TConsumer* consumer) { consumer_ = consumer; } TConsumer* consumer_; }; struct AppleConsumer { }; struct MeatConsumer { }; struct ShillyShallyProducer : public Producer<AppleConsumer>, public Producer<MeatConsumer> { }; int _tmain(int argc, _TCHAR* argv[]) { ShillyShallyProducer producer; AppleConsumer consumer; producer.SetConsumer(&consumer); // <--- Ambiguous call!! return 0; } This is the compilation error: // error C2385: ambiguous access of 'SetConsumer' // could be the 'SetConsumer' in base 'Producer<AppleConsumer>' // or could be the 'SetConsumer' in base 'Producer<MeatConsumer>' I thought the template argument lookup mechanism would be smart enough to deduce the correct base Producer. Why isn't it? I could get around this by changing Producer to template <typename TConsumer> struct Producer { template <typename TConsumer2> void SetConsumer(TConsumer2* consumer) { consumer_ = consumer; } TConsumer* consumer_; }; and call SetConsumer as producer.SetConsumer<AppleConsumer>(&consumer); // Unambiguous call!! but it would be nicer if I didn't have to...

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  • When is it better to use a method versus a property for a class definition?

    - by ccomet
    Partially related to an earlier question of mine, I have a system in which I have to store complex data as a string. Instead of parsing these strings as all kinds of separate objects, I just created one class that contains all of those objects, and it has some parser logic that will encode all properties into strings, or decode a string to get those objects. That's all fine and good. This question is not about the parser itself, but about where I should house the logic for the parser. Is it a better choice to put it as a property, or as a method? In the case of a property, say public string DataAsString, the get accessor would house the logic to encode all of the data into a string, while the set accessor would decode the input value and set all of the data in the class instance. It seems convenient because the input/output is indeed a string. In the case of a method, one method would be Encode(), which returns the encoded string. Then, either the constructor itself would house the logic for the decoding a string and require the string argument, or I write a Decode(string str) method which is called separately. In either case, it would be using a method instead of a property. So, is there a functional difference between these paths, in terms of the actual running of the code? Or are they basically equivalent and it then boils down to a choice of personal preference or which one looks better? And in that kind of question... which would look cleaner anyway?

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  • How to maintain base files for development environment central while allowing people to change their

    - by Ittai
    Hi, what I'd like to do is have files in a central location so that when I add people to my development team they can see the base version of these files but meanwhile have the ability for the rest of the team to work with their own local version. I know I can just put the files in source-control (we use Tortoiese-SVN) and have my team change the local versions but I'd rather not as the exclamation mark signaling the file has been changed and needs to be committed, quite frankly, irritates me greatly. I'll give two examples of what I mean: We use quite a few build.xml files which relate to a single properties files which contains many definitions. Some of them can be different between team-members (mainly temporary working directories) and I'd like a new team-member to have the ability to get the properties file with the base config but change it if they wish. Have the eclipse settings file in the SVN so that when a new team-member joins they can just retrieve the files from the server and have a base system running. If they wish they will be able to change some of these settings. Thanks, Ittai

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  • Declaring a string array in class header file - compiler thinks string is variable name?

    - by Dave
    Hey everybody, I need a bit of a hand with declaring a string array in my class header file in C++. atm it looks like this: //Maze.h #include <string> class Maze { GLfloat mazeSize, mazeX, mazeY, mazeZ; string* mazeLayout; public: Maze ( ); void render(); }; and the constructor looks like this: //Maze.cpp #include <GL/gl.h> #include "Maze.h" #include <iostream> #include <fstream> Maze::Maze( ) { cin >> mazeSize; mazeLayout = new string[mazeSize]; mazeX = 2/mazeSize; mazeY = 0.25; mazeZ = 2/mazeSize; } I'm getting a compiler error that says: In file included from model-view.cpp:11: Maze.h:14: error: ISO C++ forbids declaration of ‘string’ with no type Maze.h:14: error: expected ‘;’ before ‘*’ token and the only sense that makes to me is that for some reason it thinks I want string as a variable name not as a type declaration. If anybody could help me out that would be fantastic, been looking this up for a while and its giving me the shits lol. Cheers guys

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  • Use Struct as a Ptr/class? Need a fix .NET

    - by acidzombie24
    I wrote a bunch of code and i would like to fix it the fastest way possible. I'll describe my problem in a easier way. I have apples and oranges, they are both Point and in the list apples, oranges. I create a PictureBox and draw the apple/oranges on screen and move them around and update the Point via Tag. The problem now is since its a struct the tag is a copy so the original elements in the list are not update. So, how do i update them? I consider using Point? But those seem to be readonly. So the only solution i can think of is Clear the list, iterate through all the controls then check the picturebox property to check if the image is a apple or orange then add it to a list I really only thought of this solution typing this question, but my main question is, is there a better way? Is there some List<Ptr<Point>> class i can use so when i update the apples or oranges through the tag the element in the list will update as a class would?

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  • Splitting a C++ class into files now won't compile.

    - by vgm64
    Hi. I am teaching myself to write classes in C++ but can't seem to get the compilation to go through. If you can help me figure out not just how, but why, it would be greatly appreciated. Thank you in advance! Here are my three files: make_pmt.C #include <iostream> #include "pmt.h" using namespace std; int main() { CPMT *pmt = new CPMT; pmt->SetVoltage(900); pmt->SetGain(2e6); double voltage = pmt->GetVoltage(); double gain= pmt->GetGain(); cout << "The voltage is " << voltage << " and the gain is " << gain << "." <<endl; return 0; } pmt.C #include "pmt.h" using namespace std; class CPMT { double gain, voltage; public: double GetGain() {return gain;} double GetVoltage() {return voltage;} void SetGain(double g) {gain=g;} void SetVoltage(double v) {voltage=v;} }; pmt.h #ifndef PMT_H #define PMT_H 1 using namespace std; class CPMT { double gain, voltage; public: double GetGain(); double GetVoltage(); void SetGain(double g); void SetVoltage(double v); }; #endif And for reference, I get a linker error (right?): Undefined symbols: "CPMT::GetVoltage()", referenced from: _main in ccoYuMbH.o "CPMT::GetGain()", referenced from: _main in ccoYuMbH.o "CPMT::SetVoltage(double)", referenced from: _main in ccoYuMbH.o "CPMT::SetGain(double)", referenced from: _main in ccoYuMbH.o ld: symbol(s) not found collect2: ld returned 1 exit status

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  • Python base classes share attributes?

    - by tad
    Code in test.py: class Base(object): def __init__(self, l=[]): self.l = l def add(self, num): self.l.append(num) def remove(self, num): self.l.remove(num) class Derived(Base): def __init__(self, l=[]): super(Derived, self).__init__(l) Python shell session: Python 2.6.5 (r265:79063, Apr 1 2010, 05:22:20) [GCC 4.4.3 20100316 (prerelease)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import test >>> a = test.Derived() >>> b = test.Derived() >>> a.l [] >>> b.l [] >>> a.add(1) >>> a.l [1] >>> b.l [1] >>> c = test.Derived() >>> c.l [1] I was expecting "C++-like" behavior, in which each derived object contains its own instance of the base class. Is this still the case? Why does each object appear to share the same list instance?

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  • C++ iterator and const_iterator problem for own container class

    - by BaCh
    Hi there, I'm writing an own container class and have run into a problem I can't get my head around. Here's the bare-bone sample that shows the problem. It consists of a container class and two test classes: one test class using a std:vector which compiles nicely and the second test class which tries to use my own container class in exact the same way but fails miserably to compile. #include <vector> #include <algorithm> #include <iterator> using namespace std; template <typename T> class MyContainer { public: class iterator { public: typedef iterator self_type; inline iterator() { } }; class const_iterator { public: typedef const_iterator self_type; inline const_iterator() { } }; iterator begin() { return iterator(); } const_iterator begin() const { return const_iterator(); } }; // This one compiles ok, using std::vector class TestClassVector { public: void test() { vector<int>::const_iterator I=myc.begin(); } private: vector<int> myc; }; // this one fails to compile. Why? class TestClassMyContainer { public: void test(){ MyContainer<int>::const_iterator I=myc.begin(); } private: MyContainer<int> myc; }; int main(int argc, char ** argv) { return 0; } gcc tells me: test2.C: In member function ‘void TestClassMyContainer::test()’: test2.C:51: error: conversion from ‘MyContainer::iterator’ to non-scalar type ‘MyContainer::const_iterator’ requested I'm not sure where and why the compiler wants to convert an iterator to a const_iterator for my own class but not for the STL vector class. What am I doing wrong?

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  • How do I use the Enum value from a class in another part of code?

    - by ChiggenWingz
    Coming from a C# background from a night course at a local college, I've sort of started my way in C++. Having a lot pain getting use to the syntax. I'm also still very green when it comes to coding techniques. From my WinMain function, I want to be able to access a variable which is using an enum I declared in another class. (inside core.h) class Core { public: enum GAME_MODE { INIT, MENUS, GAMEPLAY }; GAME_MODE gameMode; Core(); ~Core(); ...OtherFunctions(); }; (inside main.cpp) Core core; int WINAPI WinMain(...) { ... startup code here... core.gameMode = Core.GAME_MODE.INIT; ...etc... } Basically I want to set that gameMode to the enum value of Init or something like that from my WinMain function. I want to also be able to read it from other areas. I get the error... expected primary-expression before '.' token If I try to use core.gameMode = Core::GAME_MODE.INIT;, then I get the same error. I'm not fussed about best practices, as I'm just trying to get the basic understanding of passing around variables in C++ between files. I'll be making sure variables are protected and neatly tucked away later on once I am use to the flexibility of the syntax. If I remember correctly, C# allowed me to use Enums from other classes, and all I had to do was something like Core.ENUMNAME.ENUMVALUE. I hope what I'm wanting to do is clear :\ As I have no idea what a lot of the correct terminology is.

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  • Matching Class arrays

    - by frinkz
    I'm writing a routine to invoke methods, found by a name and an array of parameter Class values Matching the Method by getName works, but when trying to match the given Class[] for parameters, and Method.getParameterTypes(), I'm having trouble. I assumed that this would work: Class[] searchParams = new Class[] { float.class, String.class }; Class[] methodParams = m.getParameterTypes(); if(methodParams == searchParams) { m.invoke(this, paramValues); } But apparantly not - m.invoke is never reached. I've checked, and methodParams gives the same classes as searchParams. The code below works, and picks the right method, but it seems like a very dirty way of doing things, I'm sure I'm missing something obvious. Class[] searchParams = new Class[] { float.class, String.class }; Class[] methodParams = m.getParameterTypes(); boolean isMatch = true; for(int i = 0; i < searchParams.length; i++) { if(!searchParams.getClass().equals(methodParams.getClass())) { isMatch = false; } } if(isMatch) { m.invoke(this, paramValues); }

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  • Multiple collections tied to one base collection with filters and eventing

    - by damienc88
    I have a complex model served from my back end, which has a bunch of regular attributes, some nested models, and a couple of collections. My page has two tables, one for invalid items, and one for valid items. The items in question are from one of the nested collections. Let's call it baseModel.documentCollection, implementing DocumentsCollection. I don't want any filtration code in my Marionette.CompositeViews, so what I've done is the following (note, duplicated for the 'valid' case): var invalidDocsCollection = new DocumentsCollection( baseModel.documentCollection.filter(function(item) { return !item.isValidItem(); }) ); var invalidTableView = new BookIn.PendingBookInRequestItemsCollectionView({ collection: app.collections.invalidDocsCollection }); layout.invalidDocsRegion.show(invalidTableView); This is fine for actually populating two tables independently, from one base collection. But I'm not getting the whole event pipeline down to the base collection, obviously. This means when a document's validity is changed, there's no neat way of it shifting to the other collection, therefore the other view. What I'm after is a nice way of having a base collection that I can have filter collections sit on top of. Any suggestions?

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  • iPhone: Using static library in an application crashes the device but not the iphone simulator

    - by spin-docta
    I have a library I made, and now I want to utilize it in an application. I've believe I've properly linked to the library. Here are all the things I've done: Set the header search path Set other linker flags to "-ObjC" Added the static library xcode project Made sure the lib.a was listed as a framework target Added the library as a direct dependency Like I said in the title, I've successfully run the app with the static library in the simulator. Once I try testing the app using the device, it crashes the second it has to use a function from the library: *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** +[NSDate firstOfCurrentMonth]: unrecognized selector sent to class 0x3841bb44' 2009-10-10 12:45:31.159 Basement[2372:207] Stack:

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  • Assembly reference in Silverlight class library and used only in xaml is not packaged in XAP

    - by Brandon Copeland
    I have a 3rd party library (A). That library is referenced in my Silverlight class library (B). That Silverlight class library is referenced in my Silverlight application (C). The 3rd party library is not explicitly referenced in the Silverlight application. It seems that "A" is added to my XAP if "A" is used in any class in "B" because of a chain in dependencies (C - B - A). This is the behavior I would expect and need. If "A" is never explicitly used in a C# class but only defined in Xaml, the assembly is not packaged to the XAP. Maybe "A" includes a control that is only used declaratively and never referenced otherwise. Is this behavior by design? Am I missing a property somewhere that controls this? I would prefer to not explicitly reference the third party library in my Silverlight application. What's to best practice to ensure all necessary assemblies are packaged in the XAP?

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  • Trying to include a library, but keep getting 'undefined reference to' messages

    - by KU1
    I am attempting to use the libtommath library. I'm using the NetBeans IDE for my project on Ubuntu linux. I have downloaded and built the library, I have done a 'make install' to put the resulting .a file into /usr/lib/ and the .h files into /usr/include It appears to be finding the files appropriately (since I no longer get those errors, which I did before installing into the /usr directories). However, when I create a simple main making a call to mp_init (which is in the library), I get the following error when I attempt to make my project: mkdir -p build/Debug/GNU-Linux-x86 rm -f build/Debug/GNU-Linux-x86/main.o.d gcc -c -g -MMD -MP -MF build/Debug/GNU-Linux-x86/main.o.d -o build/Debug/GNU-Linux-x86/main.o main.c mkdir -p dist/Debug/GNU-Linux-x86 gcc -o dist/Debug/GNU-Linux-x86/cproj1 build/Debug/GNU-Linux-x86/main.o build/Debug/GNU-Linux-x86/main.o: In function 'main': /home/[[myusername]]/NetBeansProjects/CProj1/main.c:18: undefined reference to `mp_init' collect2: ld returned 1 exit status make[2]: *** [dist/Debug/GNU-Linux-x86/cproj1] Error 1 So, it looks like the linker can't find the function within the library, however it IS there, so I just don't know what could be causing this. Any help would be appreciated. I get the same error if I type the gcc command directly and skip the makefile, I also made sure the static library got compiled with gcc as well. Edited to Add: I get these same errors if I do the compile directly and add the library with -l or -L: $ gcc -l /usr/lib/libtommath.a main.c /usr/bin/ld: cannot find -l/usr/lib/libtommath.a collect2: ld returned 1 exit status $ gcc -llibtommath.a main.c /usr/bin/ld: cannot find -llibtommath.a collect2: ld returned 1 exit status $ gcc -Llibtommath.a main.c /tmp/ccOxzclw.o: In function `main': main.c:(.text+0x18): undefined reference to `mp_init' collect2: ld returned 1 exit status $ gcc -Llibtommath.a main.c /tmp/ccOxzclw.o: In function `main': main.c:(.text+0x18): undefined reference to `mp_init' collect2: ld returned 1 exit status I am very rusty on this stuff, so I'm not sure I'm using the right command here, in the -L examples are the libraries being found? If the library isn't being found how on earth do I get it to find the library? It's in /usr/lib, I've tried it with the .a file in the current directory, etc. Is there an environment variable I need to set? If so, how, etc. Thanks so much for the help. I've tried a completely different library (GMP) and had the EXACT same problem. This has got to be some kind of Ubuntu environment issue? Anyone have any idea how to fix this?

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  • Exposing headers on iPhone static library

    - by leolobato
    Hello guys, I've followed this tutorial for setting up a static library with common classes from 3 projects we are working on. It's pretty simple, create a new static library project on xcode, add the code there, a change some headers role from project to public. The tutorial says I should add my library folder to the header search paths recursively. Is this the right way to go? I mean, on my library project, I have files separated in folders like Global/, InfoScreen/, Additions/. I was trying to setup one LOKit.h file on the root folder, and inside that file #import everything I need to expose. So on my host project I don't need to add the folder recursively to the header search path, and would just #import "LOKit.h". But I couldn't get this to work, the host project won't build complaining about all the classes I didn't add to LOKit.h, even though the library project builds. So, my question is, what is the right way of exposing header files when I setup a Cocoa Touch Static Library project on xCode?

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  • does adding static library need xcode project of static library for linking?

    - by mirdad
    I have seen some static library projects in iOS.I see two different types of linking static library. 1)adding .a static library to new xcode project and its header files only. 2)adding .a static library to new xcode project and adding the xcode project through which static library has created. when I remove the the xcode project through which static library has created from the 2nd project, it gives error.I tried first approach for 2nd one.But it is not working. Can you please explain why it is differed? Will it be differed by the xcode versions we use? is The second approach for old xcode versions?

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