Friend Classes : class definition « Class « C++ Tutorial

1. C++ Tutorial
2. Class
3. class definition

#include <iostream>
using namespace std;
   
class TwoValues {
  int a;
  int b;
public:
  TwoValues(int i, int j) { a = i; b = j; }
  friend class Min;
};
   
class Min {
public:
  int min(TwoValues x);
};
   
int Min::min(TwoValues x)
{
  return x.a < x.b ? x.a : x.b;
}
   
int main()
{
  TwoValues ob(10, 20);
  Min m;
   
  cout << m.min(ob);
   
  return 0;
}