473,847 Members | 1,542 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Accessing private members and member functions of a class C++

105 New Member
Hi all,

I have some data members and member functions that are declared as private in a class A.

Now I want to use these data members and functions(which are private) in my new C++ source file(.cpp file).I have created pointer to this class A, and tried to use the functions but I am getting an errror that: cannot access private data member.

Could anyone please help me with this?Thanks

Example :
///abc.cpp file (my source file)

main( )
A *a; // (Class A)
a -> ind(c,b); //ind is private member function of class A
Apr 5 '07 #1
2 2604
9,065 Recognized Expert Moderator Expert
Declaring member functions/data as private indicates that only the class itself may access them.

If you want to access them externally to the class you should declare them public.

If you want to restrict access to the class it self plus any derived classes then declare them protected.

A friend declaration can be used to get round the access specifier for a specific class or function.
Apr 5 '07 #2
9,208 Recognized Expert Moderator Expert
Whenever you have class private data members, write public member functions to access them.

Do not ever make the data member public.

Public data members break encapsulation. That means your implementation in the class has been exposed to the entire program. Later if you need to re-designthe class you will find yourself redesigning every bit of code that ever used your class becuse your data member names are used all over.
Apr 6 '07 #3

Sign in to post your reply or Sign up for a free account.

Similar topics

by: Wolfgang Jeltsch | last post by:
Hello, I want to write a list class with an iterator class as an inner class. The iterator class must have access to certain private members of the list class in order to do its job. Here is a reduced code example: class List { private: void *rootNode; class Iterator {
by: CoolPint | last post by:
I read in books that nested class cannot access private members of nesting class and vice versa unless they are made friends. Somehow, my compiler is letting my nested class member functions access private members of nesting class. template <typename T> class Container { // NO friendship given to any other public: class ContainerIterator;
by: Andy | last post by:
1) Is there any use of defining a class with a single constructor declared in private scope? I am not asking a about private copy constructors to always force pass/return by reference. 2) Is this in any way used to create singletons. Can someone say how? Cheers, Andy
by: Chris Mantoulidis | last post by:
Forgive me if I'm wrong but I think there is something like an extra member scope in classes. for example: class abc { ostream & operator << (ostream &, const abc &); istream & operator >> (istream &, abc &); private:
by: Sandeep | last post by:
Hi, In the following code, I wonder how a private member of the class is being accessed. The code compiles well in Visual Studio 6.0. class Sample { private: int x; public:
by: Steven T. Hatton | last post by:
I find the surprising. If I derive Rectangle from Point, I can access the members of Point inherited by Rectangle _IF_ they are actually members of a Rectangle. If I have a member of type Point in Rectangle, the compiler tells me Point::x is protected. I would have expected Rectangle to see the protected members of any Point. Compiling the following code give me this error: g++ -o rectangle main.cc main.cc: In member function `size_t...
by: __PPS__ | last post by:
Hello everybody, today I had another quiz question "if class X is privately derived from base class Y what is the scope of the public, protected, private members of Y will be in class X" By scope they meant public/protected/private access modifiers :) Obviously all members of the base privately inherited class will be private, and that was my answer. However, the teacher checked my answers when I handed in, and the problem was that I had...
by: harry | last post by:
Hi ppl I have a question about memory layout of a class. Consider the code below: class Base1 { virtual void f() { cout << "Base1::f" << endl; } virtual void g() { cout << "Base1::g" << endl; } }; class Drive : public Base1{
by: Bhawna | last post by:
I am into c++ code maintenance for last 3-4 years but recently I am put into design phase of a new project. Being a small comapany I dont have enough guidance from seniors. Currently I am into a situation where I am implementing base class functions by including a pointer to subclass member in base class. Reason being functionality is common for subclasses but the members are common within subclass only (static member of subclass) but...
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms. Adolph will...
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.
by: bsmnconsultancy | last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.