Whenever my copy constructor is called, my destructor destroys is immediately after.
My copy constructor
CS1CStudent::CS1CStudent(const CS1CStudent& otherCS1CStudent)
{
cout << "
***************************
";
[Code]....
The copy constructor is called twice, once when you pass an object by value, and once when the object is returned from a function by value. But why is the destructor being called twice?
Why in this code the destructor is called 2 time? How can i avoid it?
int _tmain(int argc, _TCHAR* argv[]) {
Elenco e1;
std::cout << "Test 2" <<std::endl;
std::cout<<e1.size()<<std::endl;
[Code] ....
Why does the destructor is called just after declaring my object?
// MAIN
int main(void) {
Jucarie j1;
Jucarie j2(j1);
return 0;
}
THE DESTRUCTOR
Jucarie::~Jucarie() {
cout << "Destructor called" << endl;
delete[] material;
material = NULL;
}
I do not have a copy constructor, i just want to use the shallow copy. Why i get Debug Assertion Failed error? If i delete the destructor, all work fine.
I get it, the problem occurs when the material from j1 is deleted right? Because it has already been delete by j2.
I have a class Square that is composed of two Points, I pass the former to the Square as references (second ctor) and two Points are created.
The problem is, at the end of the program, 4 Points are now being deleted which suggests that somewhere copies were made (regardless of the references) and the m_p1, m_p2 have different addresses than p1 and p2.
#include <iostream>
using namespace std;
class Point {
public:
Point();
Point(double x,double y);
double printCor() const;
[Code] .....
Even though, the objects were passed to the ctor by references, the copy constructor (compiler generated) for Point was called and now we have two points and an object square with distinct Point objects.
Class Car{
Private:
string* _ID;
bool _isFaulty;
int _location;
int _timer;
int _order;
vector<Road*> _roadPlan;
}
I want to implements Copy constructor (deep copy) and destructor, and I don't know how to treat the vector of pointers (Road is an object too)
Mor
Another thing, maybe I'll prefer using List instead of Vector, so i would like to see an implements of Copy constructor and destuctor with List too,
The following are the cases when copy constructor is called.
1)When instantiating one object and initializing it with values from another object.
2)When passing an object by value.
3)When an object is returned from a function by value.
I don't understand #2 How can and object be passed by value? when I think of passing object I think of passing by address or reference. explain
I don't understand #3 how can a function returned object by value I think of again passing by address or reference.
I was wondering that why in the below code, the copy constructor is called 2 times.
Code:
class A {
private:
static int count;
int age;
public:
A()
[code].....
I think that when f(a) is called, since I am passing this as value, no copy constructor should be called. The copy constructor should called when the return object "x" is assigned to:
A b = x;
why copy constructor called 2 times?
#include<iostream>
using namespace std;
class Cents {
public:
int m_nCents;
Cents(int nCents=0):m_nCents(nCents){
cout<<"Calling normal constructor with value:"; m_nCents = nCents;
cout<<m_nCents<<endl;
[code].....
Question is :Why is the overloaded copy constructor that I have written not getting called here?Internally default copy constructor is getting called.Thats why we get value of obj2.m_nCents as 37.
I have the following classes and 'dreaded diamond':
A
/
/
B C
/
/
D
|
|
E
Classes B & C both inherit from A using public virtual A.
E is the only concrete class. None of the classes are totally abstract.
Every class has a copy constructor.
All of the copy constructors are chained together through the initialization lists.
E correctly calls D's copy constructor.
D correctly calls B and C's copy constructors.
But neither B nor C call A's copy constructor, although A's default constructor is called. To reiterate B and C have a call to A's copy constructor in their initialization lists.
I guess A's default constructor is being called is because of virtual inheritence, but why isn't its copy constructor called (too)?
A's copy constructor includes some very important code and I could do with calling it. Should I call it from the concrete class' initialization list or is that considered bad form?
I have a query regarding virtual destructor functionality. So below is sample code:
Code:
#include<iostream>
#include<stdlib.h>
using namespace std;
class Base
Code: Base *b = d;
Here b and d now pointing to same memory location.
Now below statement:
Code: delete (b);
Here since my destructor is virtual it will call derived class and base class destructor.
Now my question is, if I use this:
Code: delete (d); // And without virtual keyword in ~Base() {} This call both derived and base class destructor.
So which one is correct form to call and why? Is delete(b) is standard in virtual function mechanism.
Output is:
D1 :: function1()
Base :: function2()
INSIDE D1 DES
INSIDE BASE DES
Let's start with something from the c++ reference:
... delete[] is an operator with a very specific behavior: An expression with the delete[] operator, first calls the appropriate destructors for each element in the array (if these are of a class type) ...
I was wondering if I can tell delete[] to not call destructors, for example if I already know that the delete[] statement should be delete without []. That would be very useful for memory management/memory leak detection.
I have the following code. The destructor throws a segmentation fault when it gets called. My first instinct is that there's something screwy with the array allocation.
#ifndef ARRAYLIST_H
#defineARRAYLIST_H
#include <iostream>
#include "Exceptions.h"
using namespace std;
template <class T>
class ArrayList {
[Code] .....
It's specifically the memory clearance in the destructor that throws the segfault.
I get a runtime error when I add a destructor to my code.
Code:
#include <iostream>
#include <array>
using namespace std;
struct nodes { int* elements; };
class heap
[code]....
Lets say we have a class that holds a pointer member to another object. If I delete that pointer in the destructor I get an error (and I understand why). My question is : is it possible to overcome that without memory leaks ?
1 #include<iostream>
2 using namespace std;
3
4 class A {
5 public:
6 ~A() {
7 cout<< "~A()" <<endl;
[Code] ....
I wrote the following program, it can be compiled and run, but there is warning saying that if virtual function is defined, there should be a destructor. How to do that I tried many different ways I can thought of, but none of them works.
#include <iostream>
using namespace std;
class cell_c {
public:
double p;
cell_c() {p=1;}
virtual void print() {cout<<p<<endl;}
[code]....
I am trying to build a destructor that takes an array pointer and outputs part of a private vector and, comparing a string within the objects, overwrites the data in the array with the data in the vector. (vector and array use same class type) It then proceeds as usual.
#include <iostream>
#include <string>
#include <iomanip>
[Code].....
I am trying to write the destructor for my binary search tree. But how to write this.
I have tried
delete root; and delete [] root;
but it doesn't work.
So, here is my code.
#ifndef TREE_H
#define TREE_H
struct PersonRec {
[Code]......
Is there a way to detect whether or not a template type has a protected destructor?
I see there is std::is_destructible in C++11, but I can't tell if this will return true or false for the protected case. Also, I'm interested in finding a solution for C++03 as well.
I have a class which dynamically allocates memory for three data arrays, and as such in the destructor I told it to delete those data arrays.
However, when I've created a new class, and inherited the previous class - it will always crash AFTER running the program, unless I don't have the previous destructor present.
How can I use "delete[]" on all pointers on the stack, using a mixture of top and pop functions or variables
View 2 Replies View RelatedI have little problem which causing memory leaks.
Parent > Multiple Child(Parent parent) > Child destructor deleting parent => next Child destructor crash
Example code: without using:
class Parent {
public:
Parent() {
for(int i = 0; i < x; ++i) {
for(int j = 0; j < y; ++j)
childs[i][j] = new Child(this);
[Code] ....
If you read code, on Parent destructor i = 0 & j = 1 its going crash.
Parent will be deleted aswell, but it give me assert: _block_type_is_valid(phead- nblockuse)
An attempt to create a class which is basically a mimic of vector<int> i don't seem to know how to delete pointer x in a destructor to free memory, also on pushback and pushfront methods, i can't free y when i implement delete[] y; y=NULL; i get some NULL out put when cout 'ing the object in main, why is that happening and how do i free memory y.
#include<iostream>
using namespace std;
class vectorOfint{
int* x;
int size;
public:
vectorOfint();
[Code] .....
I am working on this project where I need a function to be called every second. At this time, I am thinking that I have to create a thread but I am clueless on how it will get called every second.
View 5 Replies View Related"Destructors for a derived class object are called in the reverse order of the constructors for the object. This is a general rule that always applies. Constructors are invoked starting with the base class constructor and then the derived class constructor, whereas the destructor for the derived class is called first when an object is destroyed, followed by the base class destructor."
But why, or is it just because, so programmers know which one and modify their destructor accordingly??
In this code:
#pragma once
#include <iostream>
class CBox // Derived class {
public:
// Constructor
explicit CBox(double lv = 1.0, double wv = 1.0, double hv = 1.0) : m_Length(lv), m_Width(wv), m_Height(hv){}
[Code] .....
Before the program ends, at return 0;
I would expect the CBox destructor to be called 3 times but it is being called 6 times? Why? Also in this code:
#pragma once
#include <iostream>
class CBox // Derived class {
public:
// Constructor
explicit CBox(double lv = 1.0, double wv = 1.0, double hv = 1.0) : m_Length(lv), m_Width(wv), m_Height(hv){}
[Code] .....
Why is the destructor called 3 times? When have you really destroyed a CBox? Doesnt emplace only create it and store it, then thats it?
[URL] .....
For pushback:
void push_back(value_type&& _Val)
{// insert by moving into element at end
if (_Inside(_STD addressof(_Val)))
{// push back an element
size_type _Idx = _STD addressof(_Val) - this->_Myfirst;
[Code] .....
I was trying some virtual mechanism then This came to my mind
#include <iostream>
using namespace std;
class A
{
[Code].....
now My concerns is that though the function f() in B was private it gets called by the pointer of class A as it is a virtual function
so is this a violation of access control?