class problem

i declared 2 class, and with a function from one class i want to access the data in the other class but im not sure how this can be done. when i tried, i kept on getting error messages.

You can make the class you need to access a friend of the class that is doing the accessing.

can u give an example code?

>can u give an example code?

Code:

---

class myclass {
  friend class some_class;
  ...
}

---

The following code allows a member function from one class to access the other class

Code:

---

#include <friendclass.h>

Class Myclass
{
    public:

    private:


friend friendclass::friendfunction(Myclass Aclass);
};

---

if you want all the member functions of one class to access the other then include friend friendclass; in the Class definition.

Code:

---

class myclass {
  friend class some_class;
  ...

---

Does this allow all methods of some_class access all members of myclass, even private members of someclass?

er.... this code dont work

Code:

---

#include <iostream.h>

class myclass {
  friend class yourclass;
        protected:
          int variable;
  public:
          myclass();
};

myclass :: myclass()
{
        variable = 1;
}

class yourclass {
        public:
          yourclass();
};

yourclass :: yourclass()
{
        cout << access.variable;
}

int main()
{
        myclass access;
  yourclass access2;
  return 0;
}

---

i get an message keep saying that Undefined SYmbol "access"
if i take off access and just leave variable, it says undefined symbol "variable"

That's because yourclass has no idea what myclass variables you've declared in main.

Code:

---

#include <iostream>

using namespace std;

class myclass {
  friend class yourclass;
protected:
  int variable;
public:
  myclass();
};

myclass :: myclass()
{
  variable = 1;
}

class yourclass {
public:
  yourclass ( myclass& );
};

yourclass :: yourclass ( myclass& access )
{
  cout << access.variable;
}

int main()
{
  myclass access;
  yourclass access2 ( access );
  return 0;
}

---

originally posted by elad

Quote:

---

Does this allow all methods of some_class access all members of myclass, even private members of someclass?

---

If you make the entire class a friend then all the member functions have access to all the data including private members yes. A friend function is the same as an ordinary function except that it can access all the members of a class without restriction.