Question

Can anyone explain the friend function of C++ with example?

Answer 1

Private members are accessed only within the class they are declared. Friend function is used to access the private and protected members of different classes. It works as bridge between classes.
include<iostream.h> class RectangleTwo; class RectangleOne { int L,B; public: RectangleOne(int l,int b) { L = l; B = b; } friend void Sum(RectangleOne, RectangleTwo); }; class RectangleTwo { int L,B; public: RectangleTwo(int l,int b) { L = l; B = b; } friend void Sum(RectangleOne, RectangleTwo); }; void Sum(RectangleOne R1,RectangleTwo R2) { cout<<"\n\t\tLength\tBreadth"; cout<<"\n Rectangle 1 : "<<R1.L<<"\t "<<R1.B; cout<<"\n Rectangle 2 : "<<R2.L<<"\t "<<R2.B; cout<<"\n -------------------------------"; cout<<"\n\tSum : "<<R1.L+R2.L<<"\t "<<R1.B+R2.B; cout<<"\n -------------------------------"; } void main() { RectangleOne Rec1(5,3); RectangleTwo Rec2(2,6); Sum(Rec1,Rec2); } Output : Length Breadth Rectangle 1 : 5 3 Rectangle 2 : 2 6 ------------------------------------------- Sum : 7 9 -------------------------------------------