Hi All,
Generally copy constructor is used to create a new object from existing object.
My question is,
Do i need to allocated memory to the pointer member variables in copy constructor. Or will they share??
2  3590 
Hai,
By default the pointer variable will use the same memory of the existing object. But if u what you can over load the copy constructor.
If u are not doing so, when ur program exists you will end up in deleting the same memory twice.
Banfa 9,065
Recognized Expert Moderator Expert
If u are not doing so, when ur program exists you will end up in deleting the same memory twice.
Which is a very bad thing to do.
In general if you class does not contain any allocated pointers it is often OK to just use the default copy constructor supplied by C++. If your class contains pointers that you have allocated memory to then you will almost certainly need to override the default copy constructor and write your own to allocate memory for the new class.
Sign in to post your reply or Sign up for a free account.
Similar topics | |
by: Bob |
last post by:
Hi,
If a class contains only built-in types and standard library objects
such as strings and vectors, is it safe to let the compiler create the
copy constructor and assignment operator, or is it advised to always
write your own?
I know you need to write your own if there is any dynamic memory
allocation etc, but I was curious as to the "correct" way in the case
of static variables.
|
by: William Payne |
last post by:
Hello, I was under the impression that if I made a class Foo and if I didn't
specify a copy constructor I would get one anyway that simply assigns the
member variables (and that won't work for dynamically allocated member
variables). Anyway, I have a program that segfaults without a copy
constructor but if I add an empty one, the segfault is gone. The code is
ugly indeed so I don't want to post it, but, in general terms, what sort of
error...
|
by: MSR |
last post by:
I have a couple of questions.
1. Copy Constructor.
class A {
private:
int a1;
double d1;
char *ptr;
|
by: chris |
last post by:
Hi all,
I need to know, what is the difference between dynamic memory
allocation, and stack allocation ?
1. If I have a class named DestinationAddress, when should I use
dynamic memory allocation to create object of that class ?
2. If it says "dynamic memory allocation", is it mean the
following code :
DestinationAddress* dest = new DestinationAddress(); // code 1
|
by: Ken |
last post by:
In C programming, I want to know in what situations we should use
static memory allocation instead of dynamic memory allocation. My
understanding is that static memory allocation like using array is
faster than malloc, but dynamic memory allocation is more flexible.
Please comment... thanks.
| | |
by: sam_cit |
last post by:
Hi Everyone,
I was just wondering, about the overloaded assignment operator for
user defined objects. It is used to make sure that the following works
properly,
obj1 = obj;
so the overloaded operator function performs the necessary copy of
obj's member in to obj1. Can't the same be done using copy
|
by: JD |
last post by:
Hi,
My associate has written a copy constructor for a class. Now I need to add
an operator = to the class. Is there a way to do it without change her code
(copy constructor) at all? Your help is much appreciated.
JD
|
by: Dijkstra |
last post by:
Hi folks!
First, this is the code I'm using to expose the problem:
------------------------------------------------------------------
#include <functional>
#include <string>
#include <iostream>
using namespace std;
|
by: amare21 |
last post by:
I am getting confused about making a 2 dimensional array of pointers allocate storage space dynamically in C++. Actually I just want the second dimension of the array to be dynamic in size. For e.g. a simpler version of what I want to do would be:
Instead of,
int p;
I would do
int *p;
int x=10; // OR available thru user input
|
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: 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...
|
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: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
|
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: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
| |
