code-9.cpp

// Program to illustrate friend function
#include<iostream>
using namespace std;
class Box{
    private:
    int length;
    public:
    Box():length(0){}
    friend int printLength(Box); // friend function
};
int printLength(Box b){
    b.length+=10;
    return b.length;
}
int main(){
    Box b;
    cout<<"Length of Box : "<<printLength(b)<<endl;
    return 0;
}