Use object of an external class

[dodoxor]

Hi.I'm doing a Visual c++2005 project. I've implemented a class A in a cpp file like this: class A {...constructor,methods,and so on }; Then i've to use an object of this class in another file(my form.h file of the graphic interface) and i want that the object is visible to all methods of this class so that i can use its properties. I've put my #include a.h but where must i have to declare it to use it as "a global variable"? I can use it only if i declare it in a method but it's not visible from the other methods. If i declare it in the constructor of the class the methods don't see the object. Thanks for answers, regards.

[Larry J Siddens]

If I under stand your question correctly, you have something like this...

class MyClass
{
public:
MyClass() { ... }
~MyClass() { ... }

void myFunction( ... );
int  getInt();
void setInt( int x );

private:
int myInt;
}

And you have your .cpp file. Then you do something like this (different source file):

#include "myClass.h"

MyClass myObject;

... Other stuff...

Then to have it global.

#include "MyClass.h"

extern MyClass myObject;

Is this what your trying to do? Larry J. Siddens

[Mark Salsbery]

Do you want a global variable or a member variable accessible to the class it belongs to? A global variable you define outside of any class... A a; A member variable is defined in a class... class MyClass { protected: //public, private - whatever is appropriate A a; ... } "Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder

[dodoxor]

I try to explain my problem... class MyClass { public: MyClass() { ... } ~MyClass() { ... } void myFunction( ... ); int getInt(); void setInt( int x ); private: int myInt; } in a .cpp file. Then I've have my form.h where i want to use an object of Myclass #pragma once namespace WinCam { using namespace System; public ref class Form1 : public System::Windows::Forms::Form { private: System::Windows::Forms::TabPage^ tabPage1; ... public: Form1(void) { InitializeComponent(); //////...... } protected: ~Form1() {... } private: System::Void Form1_Load(System::Object^ sender, System::EventArgs^ e) { //here i want to use an object of the a class. ob.Myfunction(); } private: System::String^ loadtext(void){ //here i want to use the same object. int n; n=ob.getint(); } .... Where and how must i have to declare Myclass ob=new Myclass()?? thanks, regards.

[dodoxor]

I try to explain my problem... class MyClass { public: MyClass() { ... } ~MyClass() { ... } void myFunction( ... ); int getInt(); void setInt( int x ); private: int myInt; } in a .cpp file. Then I've have my form.h where i want to use an object of Myclass #pragma once namespace WinCam { using namespace System; public ref class Form1 : public System::Windows::Forms::Form { private: System::Windows::Forms::TabPage^ tabPage1; ... public: Form1(void) { InitializeComponent(); //////...... } protected: ~Form1() {... } private: System::Void Form1_Load(System::Object^ sender, System::EventArgs^ e) { //here i want to use an object of the a class. ob.Myfunction(); } private: System::String^ loadtext(void){ //here i want to use the same object. int n; n=ob.getint(); } .... Where and how must i have to declare Myclass ob=new Myclass()?? thanks, regards.

[Mark Salsbery]

dodoxor wrote:

Where and how must i have to declare Myclass ob=new Myclass()??

Here's one possible way - adding a MyClass pointer member object, allocated in the constructor, freed in the destructor...

public ref class Form1 : public System::Windows::Forms::Form
{
private:
System::Windows::Forms::TabPage^ tabPage1;
...
protected:
MyClass *pMyClassObject;

public:
Form1(void)
{
InitializeComponent();
//////......
pMyClassObject = new MyClass();
}

protected:
~Form1()
{
delete pMyClassObject;
}

private:
System::Void Form1_Load(System::Object^ sender, System::EventArgs^ e)
{
//here i want to use an object of the a class.
pMyClassObject->Myfunction();
}

System::String^ loadtext(void)
{
//here i want to use the same object.
int n;
n=pMyClassObject->getint();
}
}

Here's another possible way - adding a MyClass member object...

public ref class Form1 : public System::Windows::Forms::Form
{
private:
System::Windows::Forms::TabPage^ tabPage1;
...
protected:
MyClass MyClassObject;

public:
Form1(void)
{
InitializeComponent();
//////......
}

protected:
~Form1()
{
}

private:
System::Void Form1_Load(System::Object^ sender, System::EventArgs^ e)
{
//here i want to use an object of the a class.
MyClassObject.Myfunction();
}

System::String^ loadtext(void)
{
//here i want to use the same object.
int n;
n=MyClassObject.getint();
}
}

"Posting a VB.NET question in the C++ forum will end in tears." Chris Maunder