C++ :: Cancel Destructor Calls In Operator
Apr 18, 2014
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.
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Jan 6, 2015
I have a multi-thred piece of code that should be fast. As I have to update a Database from time to time, I wonder if I do it in a prpoer manner with calls like this:
Task.Factory.StartNew(()=>update_execution_to_db(exec));
Those are my sporadic updates, my ongoing update have a queue and a dispatcher thread reading from the Q, I just don't want to use this overhead for the sporadic updates.
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Mar 7, 2012
Code:
class A {
virtual method1() { };
};
class B : public A {
method1() { }
}
Code:
A* a = new A();
a->method1(); // call B's method1?
Is it possible to call B's method1 in this case?
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Apr 27, 2013
This is simple recursive solution of Fibonacci number:
Code:
int fibo(int n)
{
if(n<=1)
return 1;
else
return fibo(n-1)+fibo(n-2);
}
Now the recursion will generate a large recursion tree, like if n=5, 5 will call (5-1), (5-2) or 4,3 . What I want to know is, will fibo(n-1) will be called 1st go all the way to the base case 1, then do the summation or fibo(n-2) will be called right after fibo(n-1) ?
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Feb 13, 2013
I'd like to know what happens if I use multiple calls to malloc() on one pointer (without free) in a single function. Here is the example:
void *data_thread(void *sockfd_ptr) {
int sockfd = *(int *) sockfd_ptr;
const int BUFSIZE = 5;
char recvmessage[BUFSIZE];
char *headerstr = NULL;
char *newheaderstr = NULL;
[code]....
what happens with newheaderstr every time malloc() is called. There isn't a realloc() or anything. I didn't think it looked right to keep using malloc() like that.
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Aug 28, 2013
The below code is taken from open source filezilla project
(FileZilla_3.7.3_srcfilezilla-3.7.3srcinterfacebookmarks_dialog.cpp)
Code:
#include <filezilla.h>
#include "bookmarks_dialog.h"
#include "sitemanager.h"
#include "ipcmutex.h"
#include "themeprovider.h"
#include "xmlfunctions.h"
BEGIN_EVENT_TABLE(CNewBookmarkDialog, wxDialogEx)
EVT_BUTTON(XRCID("wxID_OK"), CNewBookmarkDialog::OnOK)
EVT_BUTTON(XRCID("ID_BROWSE"), CNewBookmarkDialog::OnBrowse)
END_EVENT_TABLE()
I'm unable to understand what are these lines after the #include. They don't end in semicolons. Looks very much like function calls.
Are BEGIN_EVENT_TABLE, EVT_BUTTON and END_EVENT_TABLE function calls? Function calls should end with semicolons right?
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Mar 29, 2012
I created a server application but i need to know how to delete my calls to new
Code:
CBaseServer::CBaseServer() {
}
CBaseServer::~CBaseServer() {
}
void CBaseServer::Start() {
struct sockaddr_in ain;
[Code] .....
Also when I call this..
Code:
new CThreadManager();
It gives me this warning...
warning C4345: behavior change: an object of POD type constructed with an initializer of the form () will be default-initialized
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Apr 24, 2014
I have several functions doing similar things, inside their implementations, the parameters are the same, but they call different methods.
I want to create one function to make the structure easier, and reduce the duplication. I heard template might be one solution. But I am not sure how to use it in this case.
void GetA(...XXX) {
for()
{
[Code].....
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Oct 9, 2014
My function "MatrixMul" returns an int array with multiple values Let's say, res[0] and res[1]
When I'm calling the array in a for loop for multiple times, and when I'm storing the results in another array, in each iteration the results are over-written with the new results.
If the first call returns [0,1] the array will store [0,1] at index [0] and [1], which is fine, but when I'm calling the function again, the new results are stored at the same indexes [0] and [1] How can I avoid that?
The code is:
class Hill_Cipher
{
string AtoZ="ABCDEFGHIJKLMNOPQRSTUVWXYZ";
public string Hill_Cipher_Enc(string input, int[,] key)
[Code].....
For example, my outPut contains the following: "TH","IS","AT" when I'm calling the function with the first element of array "TH", it converts "T" to its equivalent number and apply some calculations and same with "H". Let's say the final answer is 20 for "T" and 30 for "H". The problem is that every time, encChars will store the values at index 0 and 1: encChars[0]=20 encChars[1]=30 When I call the function again it will store the new values at 0 and 1.... That's because I'm not changing the index value for encChars on each call, so how do I do that?
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Mar 22, 2013
I'm doing a refresher for C++ and have gotten to operator overloading. I'm trying to perform an operator overload with the insertion (<<) operator, but I have encountered a problem.
Here's my class [In a header file "Shinigami.h"]
#include<string>
namespace K{
class Quincy;
class Shinigami{
friend std::ostream& operator<<(std::ostream&, const Shinigami&);
[Code] .....
If the operator function is a friend of the 'Shinigami' class, why doesn't it recognize any of it's private members? I need it to be in this file because I'm doing a bit of association with the 'Quincy' class.
I thought it was the namespace, but I included that.
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Mar 31, 2014
Code:
scanf("%d", &a);
printf("A");
scanf("%d", &b);
prints "A" after calling scanf two times instead of between the calls (first scan, then print, then scan). I'm using GCC v4.6
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Mar 15, 2015
I'm trying to implement a code that recursively calls itself and prints the given digits in ascending order, i.e. if the number is 5, then the function will print 1 2 3 4 5. I cannot use loops in any way!
The problem I have is with keeping my variable i at a set value each time the function calls itself.
void print_ascending(int n){
int i = 1;
if(i < n) {
printf("%d", i);
i++;
print_ascending(n);
}
}
Of course, the problem with this code is it will re-initialize the variable i to 1 every single time and infinitely loop to print 1.
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Apr 8, 2014
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] ....
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Sep 17, 2013
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?
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Nov 21, 2014
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,
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Apr 19, 2013
I need to be able to disable the items on a CCheckListBox but I can't change the code that calls AddString. I know I can use the CCheckListBox::Enable function to disable an item if I have an index but I don't have the index which would be provided by AddString.
I've tried intercepting the LB_ADDSTRING message and then looping through the items in the control but the string has not been added at this point so the last item in the list is never disabled.
I used Spy++ to see what messages were being sent and I noticed that LB_GETTEXT was sent so I tried intercepting this message (ugly hack) but this caused my app to hang - I assume because of the number of times the message is sent. Is there a way to disable the items?
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Aug 29, 2014
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
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Dec 13, 2014
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.
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Jan 29, 2015
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.
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Feb 5, 2014
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]....
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Mar 20, 2013
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] ....
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Aug 22, 2014
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]....
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Mar 7, 2014
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].....
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May 12, 2013
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]......
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Mar 28, 2014
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.
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Dec 13, 2013
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.
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