Not able to understand why friend function is not working

Question

#include<iostream>
using namespace std;

class A;
void test(A &a);
class A
{
    private:
        int x;
        int y;
        friend void test();
};
void test(A &a)
{
    a.x = 1;
    a.y = 2;
    cout << a.x << " " << a.y << endl;
}
int main()
{
    A a;
    test(a);
}

The errors I am getting are as follows-

1.error: ‘int A::x’ is private within this context

2.error: ‘int A::y’ is private within this context

Aren't friend functions supposed to be able to modify private members of a class?

Even in the link you provided. width is a private property. But it is still being accessed inside the friend function — Christian Alderson, Sep 18 '20 at 13:43
I guess the `friend` method has to be declared inside the `public` scope. — Stefan Falk, Sep 18 '20 at 13:47

score 0 · Accepted Answer · edited Nov 09 '20 at 16:37

0

#include <iostream>
using namespace std;

class A { 
  private: 
    int x; 
    int y; 

  public: 
    friend void test(A &); 
};

void test(A &a) { 
  a.x=1; 
  a.y=2; 
  cout << a.x << " " << a.y << endl; 
}

int main() { 
  A a; 
  test(a); 
}

edited Nov 09 '20 at 16:37

DasElias

569
8
19

answered Sep 18 '20 at 13:39

Bhuban ghimire

86
1
6

Christian Alderson · Answer 2 · 2020-09-18T14:02:25.363

0

There was a mistake in my code: The friend definition I gave inside the class was wrong

#include<iostream>
using namespace std;

class A;
void test(A &a);
class A
{
    private:
        int x;
        int y;
        friend void test(A &a);
};
void test(A &a)
{
    a.x = 1;
    a.y = 2;
    cout << a.x << " " << a.y << endl;
}
int main()
{
    A a;
    test(a);
}

edited Sep 18 '20 at 14:02

answered Sep 18 '20 at 13:49

Christian Alderson

71
6

Not able to understand why friend function is not working

2 Answers2