How can i provide printing for whole hierarchy of classes?, C/C++ Programming

Assignment Help:

A: Provide a friend operator<< which calls a protected virtual function

class Base {

public:

friend std::ostream& operator<< (std::ostream& o, const Base& b);

... protected:

virtual void printOn(std::ostream& o) const;

};

inline std::ostream& operator<< (std::ostream& o, const Base& b)

{ b.printOn(o); return o;

}

class Derived : public Base {

protected:

virtual void printOn(std::ostream& o) const;

};

The ending result is that operator<< acts as if it were bound dynamically, even though it's a friend function. It is called the Virtual Friend Function Idiom.

Note down that derived classes override printOn(std::ostream&) const. Particularly, they do not provide their own operator<<.

Of course if Base is an ABC, Base::printOn(std::ostream&) const may be declared pure virtual using the "= 0" syntax.

!    

 


Related Discussions:- How can i provide printing for whole hierarchy of classes?

What is structure, What is Structure? An Array is a data structure who...

What is Structure? An Array is a data structure whose elements are all of the similar data type. The structure is a data structure whose individual elements are able to differ

Decoding smugglers message, Smugglers are becoming very smart day by day. N...

Smugglers are becoming very smart day by day. Now they have developed a new technique of sending their messages from one smuggler to another. In their new technology, they are send

Help finish programming assignment, how much is it to fix a small data stru...

how much is it to fix a small data struct in a sorted list that pass itemtypes. all the code is written just logical errors

Develop custom mql4 code, Develop Custom Mql4 Code/Fxdreema block Projec...

Develop Custom Mql4 Code/Fxdreema block Project Description: I need the subsequent code written in mql4 and integrated as custom block(s) in fxdreema: for each trade: C

Padovan string, write a program that counts the number of occurrences of th...

write a program that counts the number of occurrences of the string in the n-th Padovan string P(n)   program in java // aakash , suraj , prem sasi kumar kamaraj college

Palindrome, A palindrome is a string that reads the same from both the ends...

A palindrome is a string that reads the same from both the ends. Given a string S convert it to a palindrome by doing character replacement. Your task is to convert S to palindrome

Explain compound assignment operators, Compound Assignment Operators Ap...

Compound Assignment Operators Apart from the binary and the unary arithmetic operators, we also have compound assignment operators. These are +=, -=, *=, /=, %=. Using these op

Program to define an array in c, Program to define an array in c: Writ...

Program to define an array in c: Write a program to define an array and print the value of array. void main() { int a[10]={0,11,21,34,44,75,46,57,88,89},i,j,k; clr

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