Friend functions error

[JavierL]

Im doing an excercise, where i need to use a friend class and a friend function from another class to access a private member of a third class. With the 'friend class' everything when OK, but i have problems with the friend funcion, it would be very helpful if someone could see what's wrong because i cant, and im really stucked with this.

// C5_TP3.cpp : main project file.
 
#include "stdafx.h"
#include <iostream>
#include <string>
#include <conio.h>  // for _getche(), VS 2010 closes the cmd >_<
 
 
using namespace System;
using namespace std;
 
class A; // for refering to A* in class C
 
class C {
    void i(A*);
};
 
class A {
public :
    friend class B; // Friend class B
    friend void C::i(A*); // Friend function from C, this is what is giving me issues
private:
    string a;
};
 
class B{
public:
    void a(A* x);
};
 
void B::a(A* x){
    x->a= "Reporting in B friend";
    cout << x->a << endl;
    _getche();
}
 
void C::i(A* k){
    k->a = "Reporting in C friend";
    cout << k->a << endl;
    _getche();
}
 
int main(array<System::String ^> ^args)
{
    A z; B b; C c;
    b.a(&z);
    c.i(&z);
    return 0;
}

Here is the output error from vs 2010:

1>C5_TP3.cpp(22): error C2248: 'C::i' : cannot access private member declared in class 'C'
1> C5_TP3.cpp(16) : see declaration of 'C::i'
1> C5_TP3.cpp(15) : see declaration of 'C'
1>C5_TP3.cpp(53): error C2248: 'C::i' : cannot access private member declared in class 'C'
1> C5_TP3.cpp(16) : see declaration of 'C::i'
1> C5_TP3.cpp(15) : see declaration of 'C'

[newb16]

I don't think that you can access some private member x::p of a class X by declaring X and/or X::p your friend. Another way - make X access your private function by declaring X your friend - yes.

[hype261]

Your errors are not due to the friend function. Your errors are due to your class C

class C 
{ 
    void i(A*); 
};

C++ defaults to private scope for classes. So when you call c.i(&z); in your main function it is giving you an error.

Change code to

class C
{
public:
void i(A*);
};
 

[JavierL]

Yes! I knew it was something dull that I was missing, thank you, very much.