C++ Friend Interview Question:

What are the C++ friend classes? Explain its uses with an example?

Submitted by: Administrator

A friend class and all its member functions have access to all the private members defined within other class.

#include <iostream>
using namespace std;
class Numbers
{
int a;
int b;
public:
Numbers(int i, int j)
{
a = i;
b = j;
}
friend class Average;
};

class Average
{
public:
int average(Numbers x);
};

int Average:: average(Numbers x)
{
return ((x.a + x.b)/2);
}

int main()
{
Numbers ob(23, 67);
Average avg;
cout<<"The average of the numbers is: "<<avg.average(ob);
return 0;
}

Note the friend class member function average is passed the object of Numbers class as parameter.
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