It is possible to pass uninitialized object to a parent class like in the following example class C { public: C(int i): m_i(i) {}; int m_i; } class T { public: T(C & c): m_c(c) { }; C & m_c; }; class ST : public T { public: ST(): ...
For example (maybe a bit clumsy from a real life view, but just to illustrate): "User" is a case class containing user name and id. Id can be never set manually, and a User class instance with no id set has no sense. A UserBase class maintains users base and has a "getUser (name : String) : User" method returning a consistent User inst...
Hi, I have the following object model I want to get working - have been banging my head against the clone bit! Is this possible? I can't seem to get access to the SubClass constructor from within the baseclass without hard coding it. The code is for a queue of arbitrary operations that all share a lot of common functionality; new operat...
Let's say I have a father and son who should be both non abstract and i wont to go around the father c'tor what I have done is this : public class D { public D(int x) { } public D() { Console.WriteLine("D:constructor"); } } public class E:D { public E() : base(1) { Console.WriteLine("E:construc...
I'm a completely new to C++ and I'm having a very stupid problem. I have a Graph class and I need to create a copy constructor for it. This is my class: #include <igraph.h> #include <iostream> using namespace std; class Graph { public: Graph(int N); // contructor ~Graph(); // destructor Graph(const Graph& other); // Copy ...
I have two constructors which feed values to readonly fields. class Sample { public Sample(string theIntAsString) { int i = int.Parse(theIntAsString); _intField = i; } public Sample(int theInt) { _intField = theInt; } public int IntProperty { get { return _intField;...
Suppose I have a class class C { C(int a=10); }; why if I call C c; the contructor C(int =10) is called and if I call C c(); the default constructor is called? How to avoid this? I want to execute only my constructor, I tried to make the default constructor private, but it doesn't work. ...
Trying to bend by head around Javascript's take on OO...and like many others running into confusion about the constructor property. In particular, what it's significance is as I cant seem to make it have any affect. E.g. function Foo(age) { this.age = age; } function Bar() { this.name = "baz"; } Bar.prototype = new Foo(42); ...
I have a Moose object module that should accept a relatively large data structure (ds) as one of its constructor arguments. It is used to calculate some of the object's attributes. However, I do not wish to store ds itself as an attributes -- it is only needed during the construction of the object. I thought of using BUILDARGS but then ...
In the following example, I have 2 constructors: one that takes a String and one that takes a custom object. On this custom object a method "getId()" exists which returns a String. public class ConstructorTest { private String property; public ConstructorTest(AnObject property) { this.property = property.getId(); } public Constr...
I know that default constructors initialize objects to their default values, but how do we view these values? If there's a variable of type int, it is supposed to be initialized to 0. But how do we actually view these default values of the constructors? Can anyone please provide a code snippet to demonstrate the same? ...
Im sure this is simple but I've looked at it too long and I need an answer soon. I am new to C#. If I put GetCommission() within the struct I get error CS0188: The 'this' object cannot be used before all of its fields are assigned to outside the struct error CS0038: Cannot access a non-static member of outer type 'Ex5._3.Co...
I've been learning more about Python recently, and as I was going through the excellent Dive into Python the author noted here that the __init__ method is not technically a constructor, even though it generally functions like one. I have two questions: What are the differences between how C++ constructs an object and how Python "cons...
If I want to create a new object that needs certain informations like a product id or something like that but the input is bad how can I elegant manage such a case? class Product { function __construct($id) { if(is_invalid_id($id)) { return false; } } } If I initialize it this way I still get an object (since retur...
Hi, I have an abstract base class with two inherited classes. In both these classes I define a virtual method that is used by the constructor. Now I need to create a copy constructor, but I can not declare the copy constructor as virtual, but I want the method call inside it to be dependent on the type of object that is fed as argument....
Today I came across the strange ruby syntax in the Rational class: Rational(a,b) (Notice the absence of the .new()portion compared to the normal Ruby syntax). What does this mean, precisely, compared to the normal new syntax? More importantly, how do I implement something like this in my own code, and why would I implement something...
As the title states, does Ruby allow Cartesian product types? I can't find anything on it anywhere. Thanks ...
I always thought, that there are only two defaults construcors: constructor with no arguments, and copy construtor. But today I wrote something like this: First I wanted to make sure that in C++ initialization of structures in c-style is still valid.. struct Foo{ int a; bool b; char* c; double d; }; //.. Foo arr[2]={{0...
So, the question is simple to aks: How can I overwrite the constructor of a class from the outside. The Problem itself is, that i have a class which is already compiled, and it already has some constructors, but those idiots of coders removed a constructor, so i am now unable to XML(de)Serialize it... So what they have done is this: The...
I have started a web forms project using nHibernate and objectdatasources; however, I've learned that there are some limitations that I understand but do not know to handle. These limitations include 1) objectdatasources require parameterless constructors and 2) properties of the business object cannot be read-only. The problem I'm havi...