C++ The Friend Keyword

C++ Friend Functions

Normally, private members of a class can only be accessed using public methods like getters and setters. But in some cases, you can use a special function called a friend function to access them directly.

A friend function is not a member of the class, but it is allowed to access the class's private data:

class Employee {
  private:
    int salary;

  public:
    Employee(int s) {
      salary = s;
    }

    // Declare friend function
    friend void displaySalary(Employee emp);
};

void displaySalary(Employee emp) {
  cout << "Salary: " << emp.salary;
}

int main() {
  Employee myEmp(50000);
  displaySalary(myEmp);
  return 0;
}

Example Explained

• The friend function displaySalary() is declared inside the Employee class but defined outside of it.
• Even though displaySalary() is not a member of the class, it can still access the private member salary.
• In the main() function, we create an Employee object and call the friend function to print its salary.