The rule of three (also known as the Law of The Big Three or The Big Three) is a rule of thumb in C++ that claims that if a class defines one of the following it should probably explicitly define all three: destructor, copy constructor, assignment operator
Questions tagged [rule-of-three]
65 questions
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1 answer
points not accessible after QVector insert function
I am trying to follow the rule of three, however doing this has cause a problem specifically with QVector's insert function.
after adding a copy constructor and destructor, My program will produce an error where a vector of points are no longer…
Privatized
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Why does deletion of Actor pointer result in "Program.exe has triggered a breakpoint"
I'm trying to create an Actor pointer that points to another Actor object, like so:
Actor other = Actor();
Actor* ptr = &other;
And then, when I try to delete ptr, it results in an runtime error:
Program.exe has triggered a breakpoint
But, when I…
Drin
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heap corruption detected after normal block (#181)
(first of all sorry for English , cuz I'm not good at it)
I have written a code for magic-square which works fine and gives the true square.
When it is compiled and i run the program , there is nothing wrong.
But when it reaches to the return 0 in…
Ali Samie
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how to write a class with its member is a vector of pointers to own defined class
I'm new to C++ and I'm trying to write a CarRental class which contains a vector of pointers to a base class Car.
Here's the Car class.
class Car{
public:
Car():mPlate(""), mBrand(""){}//constructor
Car(string p, string b): mPlate(p),…
Xiao Cui
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Need advise for finding correct Implementation for WrapperInterface in c++ (rule of three)
I try to find a working pattern for an interface.
Some information of what i'm doing. I'm implementing a rendering engine in dx11. My goal is to provide an easy and highly interfaced engine, where the client does not have to have any knowledge of…
kaiser
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C++ vector lose heap allocated pointer
I wrote a simple program below for the explain.
class A{
public:
int *x;
A(){ x = 0; }
~A(){ delete x; }
void foo(){
x = new int();
*x = 99;
}
};
int main(){
std::vector as;
for (int i = 0; i < 3;…
Hyunan Kwon
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1 answer
C++ Overloading assignment operator for dynamic multi dimensional array error
I'm having trouble in overloading the = operator with dynamic arrays. This is what I have so far. Also I know i havent wrote my destructor or constructor but I need to focus on this operator first:
In my header file:
#ifndef fasdf_dynn_h
#define…
Brogrammer
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2 answers
Segmentation fault; rule of three
I have a header file like this
#ifndef __coulomb_h_
#define __coulomb_h_
#include "nml_dcvector.h"
#include
#include
#include
#include
using namespace std;
class Coulomb{
public:
typedef complex…
Reza Nishat
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2 answers
Passing a class which holds Dynamic Memory : Methods and their Efficiencies
I have a class that holds some big amount of data, called HeavyData. This class Follows the rule of three (It has
overridden the copy-constructor, copy-assignment operator and the destructor to be able to copy the member variable…
user1899812
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1 answer
Class members garbled after copy-construction or copy by assignment (sometimes)
My class NRRanNormal represents a normally-distributed random variable. By default, instances are normally distributed with mean 0 and stdev 1 (i.e., a standard normal random variable).
Sometimes when I copy NRRanNormal objects, the mean and stdev…
synaptik
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1 answer
C++ : copy-and-swap idiom, alternative constructor
NB: This question follows a previous one, I hope it is okay to still ask it as a new question.
I am trying to implement the "three and a half big rule" (copy-and-swap idiom) for a tree class, which looks like this:
class Tree
{
friend void…
Seub
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1 answer
C++ Template Errors with different types
I need to find all the possible, at least three, errors from the following.
template
C myfunction(const A& a, const B& b)
{
if ( a < b ) return (C) a;
else return (C) b;
}
My answer was
typename A and B…
user2172254
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votes
1 answer
Memory Management : character arrays and = operator
Memory Management : character arrays and = operator
Q. In terms of Memory Management, What error would you have with the following code?
class String
{
public:
String(const char right[]);
String& operator= (const String& right);
int length()…
user2172254
0
votes
2 answers
C++ Destructors , dynamic allocation
I have recently had some errors (bad_alloc) due to my lack of a destructor.
I currently have two classes, set up in this way:
class ObjOne {
friend class ObjTwo;
public: //constructors and some other random methods
ObjOne(int…
Dax Durax
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-1
votes
1 answer
Destructor issues in a class with structs
I am currently facing issues while writing/utilizing a destructor for my Model class. For an OpenGL assignment I have to write a data structure which holds all the information regarding a model, see my Model.h implementation below. This class…
J. Doe
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