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POC++ - How to call creator class/object
 

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  1. POC++ - How to call creator class/object
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    <p>I need to call properties and functions of an object from a different class.</p> <p>The idea is passing 'this' as a parameter to the other class constructor. E.g.:</p> <pre><code>instance = ClassName(this); </code></pre> <p>And then do:</p> <pre><code>ParentClass parentInstance; ClassName::ClassName(MainApp _instance){ parentInstance = _instance; } </code></pre> <p>However, my compiler says that ParentClass does not name a type. Ideas? Also, should I use a pointer to save memory? How?</p> <p>Thanks in advance.</p> <hr> <p><strong>UPDATE:</strong></p> <p>Ok, sorry for the delay. Here it goes the actual code. First, a simple class.</p> <p>Game class:</p> <p>Header file</p> <pre><code>#ifndef _GAME #define _GAME #include "ofMain.h" class Game{ public: Game(); ~Game(); void hi(); }; #endif </code></pre> <p>cpp file:</p> <pre><code>#include "Game.h" Game::Game(){} Game::~Game(){} void Game::hi(){ cout &lt;&lt; "hi, I'm game! " &lt;&lt; endl; } </code></pre> <p>Then, from MainApp I create the object: - Relevant code on header file:</p> <pre><code>#ifndef _MAIN_APP #define _MAIN_APP #include "ofMain.h" #include "Game.h" class MainApp : public ofSimpleApp{ public: Game game; }; #endif </code></pre> <p>Relevant code on the cpp file:</p> <pre><code>game = Game(); game.hi(); </code></pre> <p>This obviously works as I'm only creating a bloody object. However, problem comes with composition.</p> <p>I could pass the main app as argument in the constructor, I could pass it via game.setParent(this);... problem is, I can't even define the variable to store the reference to the app.</p> <p>E.g.: (making it easy/inefficient without pointers or anything)</p> <p>Game.h:</p> <pre><code>#define _GAME #ifndef _GAME #include "ofMain.h" #include "MainApp.h" class Game{ MainApp app; public: Game(); ~Game(); void hi(); }; #endif </code></pre> <p>This returns a "does not name a type" error and declaring <code>class MainApp</code> returns an "incomplete type" error</p> <p>I'm sure I'm doing something dumb.</p> <hr> <p><strong>UPDATE 2:</strong></p> <p>The problem with that method is that I can't call a function of the pointed object now.</p> <p>This is Game.h:</p> <pre><code>#ifndef _GAME #define _GAME #include "ofMain.h" class MainApp; class Game{ public: Game(); Game(MainApp* _app); ~Game(); void hi(); MainApp* app; }; #endif </code></pre> <p>As you see, app (of the type MainApp) is passed as a parameter. That's fine, MainApp exists as it's the forward declaration. However, when I try to call any of app's functions I can't (compiler error saying Request for member appHi in .... which is non-class type 'MainApp'.</p> <p>MainApp is NOT included in Game.h but Game.h IS included in MainApp.h.</p> <p>Ideas?</p>
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    1. COPost the actual code.
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    2. COYou should probably take a look at the difference argument passing mechanisms (a brief description I worked for another question can be found [here](http://stackoverflow.com/questions/2139224/how-to-pass-objects-to-functions-in-c/2139553#2139553)) you are currently making copies instead of storing references to the parent. Besides that, I strongly agree with Neil: **show the real code**.
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      1. USDavid Rodríguez - dribeas
 

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