More Class Help

This is a discussion on More Class Help within the C++ Programming forums, part of the General Programming Boards category; Hello Again, I was hoping to get somemore class help, though this may fall under the inheritance tab as well. ...

  1. #1
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    More Class Help

    Hello Again, I was hoping to get somemore class help, though this may fall under the inheritance tab as well.

    I have two classes Class Config, and class Gui (which is a derived class of Config)
    Now to access a public variable in Config, must I reference config or can I just treat it as though it were a public variable of the Gui Class. For example, device is a public pointer in the Config class. Within my Gui constructor I reference it, please let me know if this is being done properly because when I try and call a function (even with everything in the function being commented out) I get a segmentation fault and I just cannot locate where it is occuring.

    Code:
    Gui::Gui(){
    
      env = device->getGUIEnvironment();
      prefenv = device->getGUIEnvironment();
      if(!env)
    {
        printf("oopsie, env is bad.\n");
        return;
    }
    if(!prefenv)
    {
        printf("oopsie, prefenv is bad.\n");
        return;
    }
      
    }
    Jeff Paddon
    Undergraduate Research Assistant
    Physics Department
    St. Francis Xavier University

  2. #2
    ZuK
    ZuK is offline
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    Shure any public or protected member variable can be accessed by your derived class.
    We would have to see some code to tell you exactly why your Gui constructor segfaults. ( if you get that far as to a segfault your program has to be syntactically correct ).
    But keep in mind that in the constructor of Gui only the members of Config that are initialized in Config's constructor ( default constructor in this case ) are valid.
    Kurt
    Last edited by ZuK; 08-16-2006 at 09:43 AM.

  3. #3
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    Ok, well I can post some code, but it is not actually my constructor which is seg faulting it is a call to a method within the GUI class. In an attempt to find the error I have commented out everything in the fucntion who's call is causing the seg. fault. and it is still occuring. I will post both of my classes here however.

    Code:
    class Config {
    public:
    // Variables
      core::stringw HelpText;
      int header;
      stringc str1, str2, str3, c1, c2, c3, c4;
      int header_lines, format_cols, driverType_int;
      IrrlichtDevice *device;
      ISceneManager* smgr;
      IVideoDriver* driver;
      video::E_DRIVER_TYPE driverType;
    
    // Functions
    	      Config();
    	     ~Config();
       void ReadXML(void);
       void writeConfigFile();
       void updatePref();
    };
    Code:
    class Gui : public Config  {
    public:
    // Variables
      IGUIStaticText* fpstext;
      IGUIStaticText* timetext;
      IGUIStaticText* frametext;
      IGUIEnvironment* env;
      IGUIEnvironment* prefenv;
        
         	Gui();
    	   ~Gui();
     void createGUI();
     void showPref();
     void showAboutText();
     
    };
    This is the function which is causing the seg. fault.

    Code:
    void Gui::createGUI()
    { /*printf("Creating GUI..\n");
      //IGUIToolBar* bar = env->addToolBar();
      printf("Toolbar Created..\n");
      //env->addStaticText(L"Constant Path: ", core::rect<s32>(8,10,90,25), false);
      //IGUIEditBox* namebox = env->addEditBox(L"Test/X", core::rect<s32>(100,8,240,25), true, bar, 901);
      printf("Const. Path Box Created..\n");
      //env->addStaticText(L"Start#:", core::rect<s32>(250,10,300,25), false);
      //IGUIEditBox* range1box = env->addEditBox(L"1", core::rect<s32>(310,8,350,25), true, bar, 902);
      printf("Range1 Box Created..\n");
      //env->addStaticText(L"End#: ", core::rect<s32>(360,10,410,25), false);
      //IGUIEditBox* range2box = env->addEditBox(L"1", core::rect<s32>(420,8,470,25), true, bar, 903);
      printf("Range2 Box Created..\n");
      //IGUICheckBox* sphere_check_box = env->addCheckBox (true,core::rect<s32>(490,8,510,25) , bar, 400, L"Spheres");
      //IGUICheckBox* box_check_box = env->addCheckBox (false,core::rect<s32>(530,8,550,25), bar, 400, L"Boxes");
      printf("Check Boxes Created..\n");
      //IGUIButton* launchbutton = env->addButton(core::rect<s32>(570,8,600,25), bar, 1101, L"Launch");
      printf("Launch Button Created..\n");
      //fpstext = env->addStaticText(L"", core::rect<s32>(850,8,900,25), true);
      //timetext = env->addStaticText(L"", core::rect<s32>(910,8,1010,25), true);
      //frametext = env->addStaticText(L"", core::rect<s32>(1020,8,1150,25), true);
      printf("Static Text's Created..\n");
    
      //IGUIButton* helpbutton = env->addButton(core::rect<s32>(1750,8,1790,25), bar, 1102, L"Help");
      //IGUIButton* prefbutton = env->addButton(core::rect<s32>(1650,8,1740,25), bar, 1103, L"Preferences");
      printf("Help and Pref. Buttons Created..\n");
    
    
    
      //IGUISkin* skin = env->getSkin();
      printf("Got Skin..\n");
      //IGUIFont* font = env->getFont("../include/fonthaettenschweiler.bmp");
      printf("Got Font..\n");
    
        //skin->setFont(font);
        printf("Font Set..\nBeginning Alpha Loop\n");
    
      	//for (s32 k=0; k<gui::EGDC_COUNT ; k++)
    	//{
     	//	SColor col = env->getSkin()->getColor((gui::EGUI_DEFAULT_COLOR)k);
    	//	col.setAlpha(255);
    	//	env->getSkin()->setColor((gui::EGUI_DEFAULT_COLOR)k, col);
    	//}
      printf("Alpha Loop Finshed..\n");
    
    
      stringw capstr = L"Visualization";
      //device->setWindowCaption(capstr.c_str());
      printf("Window Caption Set..\nGUI Finished\n"); */
    
    }
    and it is being called like follows in main.cpp

    Code:
    Gui interface;
    
    interface.createGUI();
    Jeff Paddon
    Undergraduate Research Assistant
    Physics Department
    St. Francis Xavier University

  4. #4
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    I was doing some thinking, and I think I may have figured this out. I have a question first though, when I create an instance of Gui I reconstruct config as well correct? In my main function I am using an instance of Config do control my devices and the like, and I think, if I am correct, when I call an instance of Gui I am pointing to a different device then I am using. Example below in psuedo.....

    Using the classes above...
    Code:
    Config config;
    Gui interface;
    
    config.device->run()
    interface->createGUI();
    Now the variable in create GUI called 'env', actually points to 'device' in config during intialization. Would these two instances point to the same device?? Because if not then I think I found the fault
    Jeff Paddon
    Undergraduate Research Assistant
    Physics Department
    St. Francis Xavier University

  5. #5
    ZuK
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    Since Gui inherits Config there would be two devices in your case ( unless device is a static member of Config ).
    Kurt

  6. #6
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    Well I got rid of the instance of config in my Main.cpp, however I still get this fault. Which strikes me as odd because I figured this to be the answer.
    Jeff Paddon
    Undergraduate Research Assistant
    Physics Department
    St. Francis Xavier University

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