All Questions
60 questions
0
votes
0
answers
107
views
Using Composite and Visitor pattern to render a OpenGL scenegraph
I'm trying to implement a Open GL (4.6) setup with the Composite pattern (for a scene graph with Node, Cube and TransformNode classes) and the Visitor pattern (with a DrawVisitor to handle rendenring)....
0
votes
0
answers
126
views
How to pass derived object as rvalue reference into base class pointer members using move constructor?
I implemented composite design pattern for calculating the nested mathematical expressions modeled in a binary tree. I need to hold two base class pointers *left,*right in my derived composite class. ...
- 19
1
vote
1
answer
152
views
How to avoid downcasting in composite pattern
I use a composite pattern to represent a mechanical network, which describes the mechanical behavior of a material, see e.g. the Maxwell-Wiechert model, a spring in parallel with n Maxwell Elements. A ...
- 1,226
0
votes
1
answer
331
views
Exception safety in the composite pattern
I used the composite pattern to represent devices, which I would like to shut down before killing their power (calling their dtor).
I ran into a problem trying to group the devices, especially ...
- 23
0
votes
0
answers
35
views
circular dependency in composite pattern [duplicate]
Good evening, i am implementing code based on the following class diagram
I am obviously facing a circular dependency problem because Document and his children use pointer to Ambit and vice-versa; i'...
- 57
2
votes
1
answer
298
views
Using Composite Pattern to make game menu
I'm making a game menu using a composite pattern. I want to achieve a tree structure game menu, where some leaves are pushing new state on the top of my state machine and another in options should ...
- 384
0
votes
1
answer
177
views
Returning Composite object of composite pattern doesn't return the whole object
I created a composite pattern with Component, Leaf and Composite Classes, where only the Composite Class has both a member variable vector and add method:
void add(Component *a);
vector < ...
- 31
2
votes
0
answers
140
views
C++ Builder combined with Visitor
I am designing a GUI Framework based on Composite pattern (Window class inherits from UIComponent class)
I need to implement a class that will create a window consisting of some UIComponents. I think ...
- 93
0
votes
0
answers
258
views
C++ Assignment composite operators vs simple operators combined with assignment operators
Someone can explain this practice to me?
// no
string s1("abc");
string s2 = s1 + " " + s1;
// yes
string s1("abc");
string s2 = s1;
s2 += " ";
s2 += s1;
Typically, a simple operator creates a ...
-1
votes
2
answers
908
views
How to fix "Access violation reading" error?
I set up a "parent class pointer" vector with size 2 to store its "derived class" address but seem like this vector only stores final address no matter how many address i added, so its cause "Access ...
- 23
1
vote
2
answers
7k
views
Console Application Menu with Classes C++
I am currently working on a personal project in C++, and I'm having a lot of fun learning. I just learned some ideas on using inheritance and virtual functions. I decided to create a Budget Tracking ...
3
votes
4
answers
1k
views
Composite pattern with variations in classes
I have a situation where class A, B, and C, all are derived from X to make a composite pattern.
Now A, B, and C are very similar but they do have different internal attributes. My question is how do ...
- 12.2k
0
votes
1
answer
91
views
cyclic dependency in composite structure with template specialization
Does anyone know a way to use template specialization with a custom class which is used in a composite structure?
To be specific, I'm writing a program to parse/validate an XML document where the ...
- 3
1
vote
1
answer
271
views
Composite pattern of std::functions
I am trying to implement a composite pattern for std::functions with use of template classes, where each composite class processes the return values of its children.
So the pattern classes might look ...
- 2,828
0
votes
1
answer
1k
views
c++ base constructor lvalue to parameter
I played a bit around with composite-patterns and inheritance in c++.
It shouldn't be something special so i coded that a component has a parent as composite, the composite should derrived from ...
- 21
10
votes
1
answer
213
views
Composite property object that inhibits multiple signal emissions when all subobjects are changed
I have a simple property<T> class with a value_changed<T> which you can connect/disconnect to and receive or inhibit events when value_changed<T>::emit(T) is called. Think Qt signal/...
- 76.4k
0
votes
1
answer
1k
views
How to implement a menu using the composite pattern?
I am trying to implement a menu using the Composite Pattern, similar to what is described here.
The Component declares several functions that Composite and Leaf have in common as pure virtual. The ...
- 28
10
votes
3
answers
12k
views
Is it alright to put data members in an interface?
Recently, I've learnt about composite pattern. I want to use it in my assignment which I have to implement File and Folder classes. I realize that sub-classes like CFile and Cfolder got to have the ...
- 758
4
votes
2
answers
184
views
Inheritance class design with "irrelevant" methods
Say I have the following abstract base class:
class DLAContainer {
public:
DLAContainer() { std::random_device rd; mt_eng = std::mt19937(rd()); }
virtual void generate(std::size_t _n) = 0;
...
- 3,355
1
vote
1
answer
633
views
Composite in C++ error [no matching member function to callto 'push_back']
Hi trying to do a simple composite and i am struggling with an error when trying to add one Compenent to the composite for training
Here is the code
Component interface Inteface for drawing ...
0
votes
2
answers
2k
views
Composite pattern with visitor, what really goes in visitor and how?
Composite pattern is often used with visitor. I am trying to figure out what exactly goes into composite and what in visitor. For example if one of the composite has unique property/attribute, will it ...
- 12.2k
1
vote
1
answer
286
views
Is it okay if each composite item in composite pattern has lots of unique properties of its own?
Typical composite pattern books shows leaner examples (obviously) where all composite items are somewhat relatable and often use one common method name for illustration like name() in folder and files ...
- 12.2k
0
votes
1
answer
673
views
Does it make sense to use composite pattern in tree view?
I have a tree view where every node is a different type of item - only the label and description property is the same. Does it make sense to represent each of these node item by composite component?
...
- 12.2k
-1
votes
1
answer
123
views
Using another class as vector in a composite class
I have 2 classes, they have a composite relationship. How do I include the class as a vector in another class? Can anyone tell me how to initialize the vector as well?
class Student{
int id;
string ...
- 55
0
votes
1
answer
56
views
OOP Approach To Buffering Data In Network App
I am working on a network library for Ethernet\IP. I am looking for input on good design strategies to assemble my packets to send them out. I am using a composite pattern to represent the pieces of ...
- 505
1
vote
1
answer
591
views
setVisible return false when QWidget is integrated in QQuickPaintedItem
I was facing one issue with the Widget which is integrated in the QQuickPaintedItem class. When I have Widget integrated in the QQuickPaintedItem, QWidget::isVisible will return false. If I tried to ...
- 1,558
0
votes
1
answer
2k
views
error: C2146: syntax error : missing ';' before identifier 'm_Employer',
Along with Errors "C4430 missing type specifier int assumed" x2 , and C2061 syntax Errors Employer
Code:
Person.h
#ifndef PERSON_H
#define PERSON_H
#include "employer.h"
#...
4
votes
3
answers
371
views
C++: Applying the Composite pattern
I am trying to apply the Composite pattern, so I need to create a Leaf class and a Composite class, both inheriting from the same Component class. In order for any of my Components to perform their ...
- 3,813
0
votes
1
answer
669
views
OOP menu system
I am trying to make a menu system (with submenus) using QGraphics from Qt4.8.
The Composite Pattern sounds like a good solution but I got stuck.
This is the UML diagram:
https://i.sstatic.net/JgWpQ....
- 45
-1
votes
2
answers
5k
views
initialize a static const std::pair<string,vector<string>>
I have a
class myclass
{
// ...
static const vector<pair<string,vector<string>>> var;
// ...
};
in the class definition, to use mappings of single strings to several ...
- 2,359
0
votes
2
answers
74
views
How to automatize overriding methods?
I am wondering if there is any tricky way to override all class methods in the same manner. For instance, how to wisely implement composite pattern in large classes? When i get something like this for ...
- 10.3k
2
votes
0
answers
805
views
Drawing on overlay window of X11 ignored by gdm/metacity
I am trying to build a smaller application that draws on top of all windows shown by the X11/x-server using cairo.
I found some interesting starting points out there and got a small piece of code ...
0
votes
1
answer
334
views
GOF Composite Design Pattern CompositeObject::Remove Recursive Implementation in C++
This is the part of question from my question asked in codereview website:
GOF Composite Design Pattern Implementation Using Modern C++
The post has complete information/implementation about it but ...
- 5,731
0
votes
1
answer
208
views
Iterating through a composite state list pattern
I've been trying for ages to finish this self-assigned project. My question is specifically about the "length" function, at the bottom - is there a way to iterate through the list without passing a ...
10
votes
0
answers
565
views
ASTs: prefer inheritance or variants? [closed]
In object oriented languages, it is fairly common to implement ASTs (Abstract Syntax Trees) using simple hierarchies (the Composite pattern), and to traverse them via visitors.
In functional ...
- 8,739
2
votes
1
answer
342
views
Operation overloading in composite design pattern in C++
Suppose I have this code all set up:
class Function
{
public:
virtual double eval(double x) const =0;
};
class Polynomial : public Function
{
private:
std::vector<double> coefficients;
...
3
votes
1
answer
431
views
Memory management in the composite pattern
I am encountering the same problem over and over, in the last weeks. Boiled down to its core, I build a (directed acyclic) hierarchy of objects like:
a -> c
b -> c
b -> d
An instance can ...
- 351
1
vote
1
answer
535
views
Composite pattern: Copy tree structure
I have implemented a basic composite pattern structure having three classes:
class Component
{
};
class Leaf : public Component
{
};
class Composite : public Component
{
vector<Component> ...
- 55
1
vote
3
answers
107
views
Can some members of a class be accessible only by base classes?
I have a Widget class and a CompositeWidget that is derived from it. CompositeWidget adds child management behaviour. The Widget constructor takes a CompositeWidget* parameter as the widget parent. I ...
- 2,531
2
votes
3
answers
910
views
Composite with smart pointers without dynamic_pointer_cast
I implemented the composite pattern using smart pointers, it works until a point.
The problem is that I just can use the methods that is implemented in the interface and I can not use the methods ...
- 532
1
vote
2
answers
1k
views
Failing to see real value in Composite/Iterator design pattern
I have situation which in theory is perhaps perfect fit for composite and iterator design pattern but the problem I have with these patterns is one can't access the underlying data structure which can ...
- 12.2k
1
vote
1
answer
68
views
How to get ansestor's attribute in a tree structure?
I use composite pattern to implement a tree structure. It has 3 classes: node (base class), leaf (no child class), and branch (with children class). And I have some common data put in a tree node, ...
- 13.5k
2
votes
2
answers
586
views
Composite pattern in C++ and C# - protected virtual methods
How can I add a protected virtual method in the "Component" class, so that it can be called from the "Composite"?
As an concrete example, look at the code below, and please tell me how to avoid the ...
- 3,911
0
votes
1
answer
524
views
C++ Inheritance & composition used together
I have class A, having methods that update properties of B. So, I need inheritance.
class B{
public:
int x;
};
class A : public B{
public:
void update(int y){
x = y;
}
};
I also want to reach ...
- 2,578
2
votes
1
answer
1k
views
C++11 Composite Pattern with Smart Pointers
I am working on a personal project to familiarize myself with C++11 and Boost.
I have a inheritance relationship with a UrlExtractor base class, with a TagUrlExtractor derived class and a ...
- 8,695
0
votes
2
answers
719
views
Dereference iterator as part of a boost::bind composite chain
I am trying to use bind to produce a function that:
Receives a map m
returns m.begin()->first
For that I am trying to use boost::bind:
typedef map<int,int>::const_iterator (map<int,int>:...
- 2,792
3
votes
1
answer
4k
views
Composite, component and entities in C++ game engine
I'm working on a school project developing a game. We use an engine made by one of the teams we have. The build-up of the engine is unclear to me and seems an anti-pattern. However, it seems that no ...
- 196
7
votes
4
answers
1k
views
Solving design involving multiple inheritance and composite classes in c++
I have struggled with this design problem for some time. I will do my best to explain what I am trying to do and the various approached that I have seen, what I am trying and why.
I work in a ...
- 867
0
votes
1
answer
101
views
[C++]How to use std::stack to deal with the file/directory hierarchy?
I have 3 class, Root, CFile, SubDirectory. Root is a abstract class. CFile and SubDirectory are derived from Root. CFile has attributes: name:string , size:int, level:int. SubDirectory has attributes: ...
- 45
0
votes
3
answers
644
views
cannot convert parameter 1 from 'PrintVisitor *const ' to 'Visirot &'
I used two design pattern Composite and Visitor. I have no problem with Composite.But when he began writing derived classes for input and output got some errors, solution which I did never found. ...
