Friend functions are those function that is not a member of class. It also define the outside of class. Using friend function you can access the private and protected member of a class. Friend function declare within the class and define outside of the class. It is special type of function.
How to declare Friend Function:
For declaring friend function you can use friend keyword.
Syntax :
//within class declaration
class className {
friend functionName( parameters );
}Advantage of Friend Function:
- Friend functions can access private and protected members of a class.
- The most powerful advantage of encapsulation and data hiding is that a non-member function of the class it cannot access a member data of that particular class.
- It is very helpful for operator overloading.
Find the square of a number using friend function:
#include<iostream>
using namespace std;
Class SquareExample
{
int number;
public:
void enterNumber()
{
cout<<”Enter Any Number… “;
cin>>number;
}
friend int findSquare(SquareExample obj1);
};
int findSquare(SquareExample obj1)
{
return (obj1.number*obj1.number);
}
int main()
{
SquareExample obj;
obj.enterNumber();
cout<< “Square of a number is : ”<< findSquare(obj);
return 0;
}
