C++ :: Deleting Object From A Container?

Nov 21, 2013

I have a container in c++11 and i must delete first object and i don't know how...

for (const prob& p : *static_cast<vector<prob>*>(list.listData)){
// i must delete the first object
}

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C++ :: Deleting A String Object In Vector?

Sep 21, 2013

Here's my code so far:

case DELETE_TITLE:
std::cout << "Game to remove from list: ";
std::cin.ignore();
getline(std::cin, gameTitle);
for (iter = gameList.begin(); iter != gameList.end(); ++iter) {

[code]....

It deletes the text from the string but not the index it self.

It deletes the text but when I print the list of game titles it has it there blank. I want it to completely remove the object from the vector from where it was deleted

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C++ :: Deleting Specific Class Object In Array

Jan 23, 2013

I am trying to delete a speific element in an array of class objects. i am overwriting the element i waant to delete with the element after it. My algorithm works but the output is not correct, after debugging it seems my objects just dont copy, is there a way to copy a class object, i have looked up copy constructors and attempted to write one but it does not seem to have any effect on the output.

below is my code

class user {
string firstname, lastname, currentteam, position, status ;
int age ;
public:
user() {};

[Code] .....

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Visual C++ :: MF Dialog App - Deleting HBITMAP Object

Mar 6, 2015

I have a little demo of a bitmap button that simply uses CButton and resource bitmaps in an MFC dialog app. The intent is to click on the button and have the bitmap image change. My code works ok the first time around, but crashes on repeat clicks. I have interpreted this as failure to properly delete the HBITMAP object, though I could be mistaken. In any case the app works ok in Release configuration but violates assertion in Debug.

Code:

ASSERT(m_hObject == NULL); // only attach once, detach on destroy[code]
// dialog header
// Attributes
protected:
HBITMAP m_hBitmap1;
HBITMAP m_hBitmap2;

[Code] .....

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C++ :: Pass Object To Class Which Stores It In Container As Unique Pointer

Jul 24, 2013

class A (abstract)
class B : A
class C {
void add ( A(&*?) a )
std::vector<std::unique_ptr<A>> data; //unique_ptr<A> because A is abstract and therefore vector<A> isn't possible
}

upper situation. What is the best way to pass add an object of class B to C?

with C::add(A* a){ vector.push_back( unique_ptr<A>(a) ); }
and
int main() {
C c;
c.add( new B() );
}

This works, but i don't think it's very nice, because you could delete the pointer in main. What happens then with the unique_ptr? I could probably make C::add( std::unique_ptr<A> u_p ); but maybe it can be avoided that the "user" (in main() ) has to create the unique_ptr itself.

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C++ :: Will Copy Constructor Does Object Initialization Using Another Already Created Object

Mar 16, 2013

will copy constructor does object initialization using another already created object? I understand that it can be applied for object initialization and not for assignment.Is it correct?

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C# :: Method Is Overwriting Both Instance Of Object And Original Object

Jul 3, 2014

I have a method to take a Tile object and make an instances of it based on some data from the original object. Than it is suppose to manipulate the a specific instance and save the results. The first loop through it works but it changes all instance as well as the base.

public static int recurse(int count, Tile[,] b,Huristic h,int check) {
if (check==1) {
boardState.Add(B)/>;
return check;
} if (check == 0)

[Code] .....

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C++ :: Importance Of Static Object In A Class And How They Are Different From General Object

Dec 13, 2012

#include "B.h"
class A {
public :
A()
{
s_b = new B();
b = new B();

[Code] ....

In my project i have seen static object as above . But not able to know what is the exact use of it and how they are different from general object .

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C++ :: What STL Container Should Be Used For Inventory

Mar 27, 2014

So I'm writing an RPG and I'm in need of an inventory system. Of course as an relatively old member of the forum I know best than just come here and ask so I've already researched quite a bit and I've formulated this idea.

I've kind of conceptualized it like so: I'll have some sort of STL container of a unique_ptr of my base item class. There will be derived item classes. Taking advantage of polymorphism I can then call the new Derivedclass when inserting it in the STL container.

My questions are: What STL container should be used for the inventory(fixed sized)?

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C++ :: What Is Container Class

Sep 22, 2013

What is container class? what its advantage ?

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C++ :: Which Std Container To Choose

Sep 16, 2012

I have a pile of data, which i need to access frequently and fast. One entry consists of two unsigned ints, let`s call them source and destination.

One source can have several destinations, but this rarely ever happens. Several sources can have the same destination - this happens more frequently, but still scarcely.

Once the data is set up, it rarely ever changes - yet it should be possible to add or remove entries.

I now need to find all sources for a given destination, or all destinations for a given source.

The question: which stl container to choose?

I have tried a multimap, using the source as key. This works good for finding all d for a given s, but is inefficient in the other direction.

Do you think it would be more efficient to have two multimaps, sorted respectively by source and destination?

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C++ :: What Can't Non-const Object Receive Temporary Object

Sep 11, 2014

a function returns a temporary object like

int myfun(){
int x = 0;
return x;
}

this function will return a temporary integer now void fun1(const int & num); this function can receive from myfun().BUT void fun2(int & num); this function cannot receive from myfun() Why is that, Moreover what is lifetime of a temporary object like one returned in myfun() ???

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C# :: Constructor Object Reference Not To Set Instance Of Object

Mar 28, 2014

I am trying to use web api in order to return custom json response keys. For this i have return a custom class to return json response

Custom Class:

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;

[Code].....

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C Sharp :: Object Reference Not Set To Instance Of Object?

May 4, 2013

I have a combobox with Items 1024
2048
4096
8192

String cach = form.comboCache.SelectedItem.ToString();

I am using the above code to retrive an item selected by user,But this line is giving an exception "Null Reference Exception, Object reference not set to an instance of an object"

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C++ :: Multilevel Dynamic Container

Mar 6, 2013

I am trying to come up with a way to make use of a "multilevel dynamic" container. I am parsing a file to grab some pieces of data. Lets say the first field of data I find I push into an array. At the same time lets I wish to create 2 cascaded sublevels. So an element in Modules is a pointer to the Types vector associated with that module and each element in Types is a pointer to a vector of Data. This concept should be similar to memory paging.

/*
Modules Types Data
____ _____ ______
|____|------> |_____| ---------->|______|
|____| |_____| |______|
|____| |_____| |______|
|____|
|____|
|____| _____ ______
|____|------> |_____|----------->|______|
|____| |_____| |______|
*/

Obviously this becomes very hair quickly so it is obvious that I need to dynamically create and destroy vectors (if I do it this way). Should I just create pointers using the new operator?

Here is some of my code if it is even worthwhile to read:

class Parser {
//storage arrays
vector <string> modules;
vector <string> terminal_type;
vector <string> tag_type;
vector <string> data;

[Code] ....

parse this stuff and nicely organize it.

If you take the first one, "max_logvar" is a module so everything between < and > is associated with that module.

symb is unimportant for now.

then "proterm" is a "module type" so then module now needs a module type container but I may have more than one of those.

so then I break it down by "Input" and "Output" where each of those can have the integer values (just in an array where each position will be set) that are in the fields to the right.

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C++ :: Container Of Hierarchy Of Objects

Apr 25, 2014

How do we design a container of objects all of which belong to some subclass which directly/indirectly inherits from a given parent class? Moreover, I would like to have functions that enable me to pick only objects of a certain class type from the container.

For example if the parent class is A and I have a hierarchy of classes that derive from it, we must have a container that can contain any class that exists in this hierarchy. Also, get_B() must be able to let me examine only those objects in this container that inherit (directly/indirectly) from class B (class B exists in the hierarchy rooted at A).

Preferably, we would like to avoid downcasting. Or even explicit typechecking of any sort.

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C++ :: Relation Between A Container And Allocator

Mar 30, 2014

To my understanding, a Container should have an Allocator member data, which is used internally.

Question: what happens, for example, when we swap() two containers that use different allocators?

Must the allocators be swapped as well?

Must all elements of the container be reallocated when the allocator is changed?

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C++ :: Bidimensional Array Container

Jun 24, 2013

I need to create an array container with the same structure as double myA [100][100];. But I cannot declare it as array<double, 100, 100> myA; however I do need this container for its format. How can I make it work.

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C++ :: How To Create A Container Class

Feb 9, 2013

I know that it's a class that contains data from another class I just do not know how to make them both work together.

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C++ :: Building A Typeless Container?

Jun 14, 2013

i built a programming language called jade that right now can only print. i want to add variables to it however. I am going to use a modified bajarne stroustrop calculator to handle expressions (ie will now include string manipulations and such), but I want to build a var class into the program to make it easier for the program. i want variables to act like python variabes, and arrays to act like python associative arrays. Ive scoured different containers, but they only work if the variable isnt an array in my language, because it will only have one type. the only thing i can come up with is a union and 4 overloaded = operators (for bool, int, double, and string) is there a better way to do this?

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C++ :: How To Properly Iterate Over A Container

Oct 31, 2013

so i have a container called Source that is of type std::map<std::string, std::vector<std::string>> but when I try to print it with this function:

void Lexer::PrintSource()
{
for(auto Iterator = this->Source.begin(); Iterator != this->Source.end(); Iterator++)
for(auto SubIterator = Iterator->begin(); SubIterator != Iterator->end(); SubIterator++)
cout<< *SubIterator << endl;
}

i get these errors:

Lexer.cpp: In member function 'void Lexer::PrintSource()':
Lexer.cpp:29:42: error: 'struct std::pair<const std::basic_string<char>, std::vector<std::basic_string<char> > >' has no member named 'begin'
for(auto SubIterator = Iterator->begin(); SubIterator != Iterator->end(); SubIterator++)
^
Lexer.cpp:29:76: error: 'struct std::pair<const std::basic_string<char>, std::vector<std::basic_string<char> > >' has no member named 'end'
for(auto SubIterator = Iterator->begin(); SubIterator != Iterator->end(); SubIterator++)
^

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C++ :: How To Delete A Container From A Deposit

Nov 23, 2013

I have a deposit of containers and i must delete the cats container. How i can do that?

#include <iostream>
#include <string>
#include <vector>
using namespace std;
struct Cat {
string name;
int age;

[Code] .....

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C++ :: Array Container For Loop?

May 13, 2014

I want to find all instances of a substring mysub in array container myarr and replace each occurrence of mysub with empty string " ". To do that, I'd like to use for loop with search algorithm.

Code below:

p=array iterator
for ( p=search(myarr.cbegin(),myarr.end(), mysub.begin(),mysub.end();
p!=myarr.end();
p=search(p,myarr.end(),mysub.begin(),mysub.end() ); {

[Code] ......

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C++ :: Accessing A Table By Container

Jun 30, 2014

I need a "meaningful" way of accessing a table, the column is representing Err magnitude, and the row is representing Rate magnitude. For each error magnitude and rate magnitude, i define an action magnitude, which is the contains of the table. For example,

Code:
int matrix[10][10];
int Action1 = matrix[0][0];
int Action2 = matrix[0][1];

However, i need a better way of getting matrix[0][0], row and col itself is meaningless. I want to access the table like

"Action magnitude" = matrix["Rate magnitude 1"]["Err magnitude 2"]; using a string instead of int id.

How to easily do this in c++ container?

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C++ :: Best Std Container Class For Application?

Jan 16, 2012

I have a class called CTestObject and it has one variable int id. I want to add instances of this to an std container and be able to:

1. quickly determine if the value of "int id" exists in the container and update the object

or

2. add a new object to the container

Which std container is the best for this application? What method should I use to search the container for the object id?

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C++ :: STL Container And Algorithm Requirements

Feb 21, 2012

How do you find, when you first introduced with say some of the STL container, function or algorithms, what are its requirements? I mean,

1. what operators object should have for specific container?
2. what function args and type it should return for a algo?
3. when extending some container like with custom allocator, char_traits...and what not, what methods should be overridden? What work should they do?

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