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C++ FRIEND FUNCTION & INHERITANCE.
FRIEND FUNCTION
- In encapsulation and data hiding: a non member function has no permission to access private data of the class.
- The private data members of the class are accessed only from member function of the same class. Any non-member function cannot access the private data of the class.
- C++ allows a mechanism in which a non-member function can access the private data members of the class i.e by declaring a non-member function friend of the class whose private data has to be accessed.
RULES
Not a member of any class therefore no need for scope resolution operator.
void sum::putdata(void)void disp(void)
- Friend function can be called like normal function, no need of object.(since it is not a member of any class)
a.disp();disp();
- Definition also like normal function.(no need to mention the name of the class).
- Arguments assed while calling friend function should be the object of the class.
Q) Write a program to access private data using non-member function.
Use friend function.
Q) Write a program to declare friend function in two classes. Calculate
the sum of integers of both the classes using friend sum() function.
Assignment :
Q) Write a program to exchange values between two classes using friend functions. (assignment) .
Q) Write a program to declare three classes. Declare integer array as data member in each class. perform addition of two data member arrays into array of third class. Use friend function.(assignment)
