What is some reward/drawback of using friend functions?, C/C++ Programming

Assignment Help:

A: They present a degree of freedom in the interface design options.

Member functions & friend functions are equally privileged (100% vested). The major difference is that a friend function is called such as f(x), whereas a member function is called like x.f(). Therefore the ability to select between member functions (x.f()) and friend functions (f(x)) let a designer to choose the syntax that is deemed most readable, which lowers maintenance costs.

The major disadvantage of friend functions is that they need an extra line of code while you wished dynamic binding. In order to get the effect of a virtual friend, the friend function must call a hidden (usually protected) virtual member function. It is called the Virtual Friend Function Idiom. For instance:

class Base {

public:

friend void f(Base& b);

... protected:

virtual void do_f();

...

};

inline void f(Base& b)

{

b.do_f();

}

class Derived : public Base {

public:

... protected:

virtual void do_f(); // "Override" the behavior of f(Base& b)

...

};

void userCode(Base& b)

{

f(b);

}

In userCode(Base&) , the statement f(b) will invoke b.do_f(), that is virtual. It means that Derived::do_f() will get control actually if b is a object of class Derived. Note down that Derived overrides behavior of the protected virtual member function do_f(); this does not have its own variation of the friend function, f(Base&).


Related Discussions:- What is some reward/drawback of using friend functions?

What is precedence and order of evaluation, Precedence and Order of evaluat...

Precedence and Order of evaluation The languages follow a standard precedence for basic operators. Precedence rules help in deleting ambiguity of the order of operations perfor

Structures, A more advanced data type is the structure; here we can define ...

A more advanced data type is the structure; here we can define a template as a collection of different variables e.g.     struct birthdate   {     int month;     int day;

Compter graphices, program that generate university statistical bar graph u...

program that generate university statistical bar graph using 3d function

Flowcharting., flowcharting of 3 quizes display the average

flowcharting of 3 quizes display the average

Add guts to vs 2008 c++ windows service, Add guts to VS 2008 C++ windows se...

Add guts to VS 2008 C++ windows service Project Description: I have a shell windows32 service written in 2008 VS C++. I want the functionality part started. Need someone too

Area under curve., find the c program to find area under the curvey=f(x) ...

find the c program to find area under the curvey=f(x)   #include float start_point, /* GLOBAL VARIABLES */ end_point, total_area;

C code for implementation on binary heap, what is binary heap ? what is the...

what is binary heap ? what is the c code for the implementation for the binary heap

Example for external storage class - computer programming, Example for exte...

Example for external storage class - computer programming? extern double sin (double); In a function prototype, for the sin() function its function definition ~ we can write

C program to find area of rectangle, Aim: To implement a program to find a...

Aim: To implement a program to find area of rectangle, surface area of box and volume of box using virtual functions. Code:                       class rect {

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd