473,836 Members | 1,599 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

constant member functions of a class

Hi, what is the different between the following two ways to use const
in a function definition:

1. const Array &operator=(cons t Array &);
2. int getSize() const;

keyword const to the left of return type and to the right of the
parameter list, what is the different here? I know for the 2nd case,
the function can not modify the object's data member.

Thanks a lot

-Holly

Jul 23 '05 #1
3 1502

"blueblueblue20 05" <zh******@gmail .com> wrote in message
Hi, what is the different between the following two ways to use const
in a function definition:
These are not function definitions; they are declarations.

1. const Array &operator=(cons t Array &);
The assignment operator takes a reference to const Array object and returns
a reference to const Array object too.
2. int getSize() const;


getSize takes no parameters and returns an int. It promises to not mutate
the object on which this member function has been called.

Sharad
Jul 23 '05 #2
blueblueblue200 5 wrote:
Hi, what is the different between the following two ways to use const
in a function definition:
Both below statements are function declarations and not definitions.
Definition is when you write code in the function.

1. const Array &operator=(cons t Array &); Function returns a ref to a constant array.
2. int getSize() const; If declared inside a class this means it cannot modify the values of
the class data members. I guess this can be over-ridden if you decl a
data member as mutable. Not sure though.

keyword const to the left of return type and to the right of the
parameter list, what is the different here? I know for the 2nd case,
the function can not modify the object's data member.

Thanks a lot

-Holly


Jul 23 '05 #3
they are declarations, sorry for the confusion, I just saved typing the
body of the function definition. and they are the member function of a
class. Thanks a lot, now I know the difference, one can not modify the
object itself, the other one can modify the object, but return a const
data

Jul 23 '05 #4

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

2
6524
by: srinivas reddy | last post by:
Hi, Can a constant member function be overloaded with its non-constant equivalent. I mean can void func() be overloaded with void func() const. If so what behaviour is guaranteed, how does the compiler resolve ambiguity?, and how could I call a specific variant? tia, Srinivas
5
4838
by: CoolPint | last post by:
It seems to me that I cannot assign objects of a class which has a constant data member since the data member cannot be changed once the constructor calls are completed. Is this the way it is meant to be? Am I not suppose not to have any constant data member if I am going to have the assignment operator working for the class? Or am I missing something here and there is something I need to learn about? Clear, easy to understand...
3
2112
by: archana | last post by:
Hi all, I have created one sealed class having one constant. Can i access that constant of sealed class without creating object of that class. If yes will internally new object gets created. Or will it behave like static member which remains in memory throughotut applications' lifetime. Please correct me if i am wrong.
10
1606
by: Dennis Jones | last post by:
Hello, I have a hierarchy of classes in which there will be a data element that is common to all descendant classes. This element (a string in this case) is constant, but specific to each class. So I have something like this: class Base { private: virtual std::string GetString() const = 0;
3
20883
by: johnmmcparland | last post by:
Hi all, I would like to have a static constant array inside a class definition which would contain the number of days in each month (I am writing a Date class as an exercise). However my attempts so far have been unsuccessful. Take this Test class as an example // test.hpp
13
1659
by: Anarki | last post by:
#include <iostream> using namespace std; class ConstantMember { const int m_const; public: ConstantMember(int cons = 10):m_const(cons){} int getConst() const{ return m_const;} };
7
3977
by: Immortal Nephi | last post by:
My project grows large when I put too many member functions into one class. The header file and source code file will have approximately 50,000 lines when one class contains thousand member functions. Is it normal how C++ Compiler can compile large class without any problem? Didn't C++ Compiler have rules to limit the number of member functions? One big object has complex operations how member variables and member functions can be...
8
1675
by: fabian.lim | last post by:
Hi, I have a question on constant variables. In the following code snippet, I have a function assign() that takes in an iterator to the private variable v, the number of stuff to assign (int n), and the information to assign (a const pointer to a class object Vector<TYPE>. According to the arrow below, I put a const keyword in the function. To my knowledge, this means that all private variables in this object
7
4274
by: Hendrik Schober | last post by:
Hi, this #include <string> class test { typedef std::string::size_type size_type; static const size_type x = std::string::npos; }; doesn't compile using either VC9 ("expected constant expression") or Comeau Online ("constant value is not known"). If I replace
0
10852
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
0
10553
jinu1996
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...
1
10596
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,...
0
9382
agi2029
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...
1
7793
isladogs
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...
0
5651
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...
0
5829
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
2
4021
muto222
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.
3
3116
bsmnconsultancy
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.