In a language were both are available, would you prefer to see an instance constructor or a static method that returns an instance? For example, if you're creating a string from a char[]: String.FromCharacters(chars) new String(chars) ...
Ryan Delucchi asked here in comment #3 to Tom Hawtin's answer: why is Class.newInstance() "evil"? this in response to the code sample: // Avoid Class.newInstance, for it is evil. Constructor<? extends Runnable> ctor = runClass.getConstructor(); Runnable doRun = ctor.newInstance(); so, why is it Evil? ...
I'm reading this C++ open source code and I came to a constructor but I don't get it ( basically because I don't know C++ :P ) I understand C and Java very well. TransparentObject::TransparentObject( int w, int x, int y, int z ) : _someMethod( 0 ), _someOtherMethod( 0 ), _someOtherOtherMethod( 0 ), _someMethodX( ...
Say I have a struct "s" with an int pointer member variable "i". I allocate memory on the heap for i in the default constructor of s. Later in some other part of the code I pass an instance of s by value to some function. Am I doing a shallow copy here? Assume I didn't implement any copy constructors or assignment operators or anythi...
I would like to know what is the difference between initializing a static member inline as in: class Foo { private static Bar bar_ = new Bar(); } or initializing it inside the static constructor as in: class Foo { static Foo() { bar_ = new Bar(); } private static Bar bar_; } ...
I find that most books concerning C++ templates don't tell anything about whether it's possible or not to use initialization list in constructor of a template class. For example, I have code like this: template <class T> class Stack { T* data; std::size_t count; std::size_t capacity; enum {INIT = 5}; public: Stack()...
I would like to use Class.newInstance() but the class I am instantiating does not have a nullary constructor. Therefore I need to be able to pass in constructor arguments. Is there a way to do this? ...
Hi, A while back I asked about instantiating a HttpContext object. Now that I have learnt what I didn't know, what confuses me is that you cannot say HttpContext ctx = new HttpContext(); because the object does not have a constructor. But doesn't every class need a constructor? In C#, if you don't provide one, the compiler automaticall...
Exactly what the title says. I'm using MSVC++ 2008 express, and my class constructor is never executed when compiled in release mode. It DOES work in debug mode. I am doing something like: ClassTest test; test.DoIt(); Breakpoints on DoIt(); trigger, but breakpoints on ClassTest::ClassTest(); do not. ...
C++: Since a struct is a class with everything "public", are default -ctors created and called? The reason I ask is to understand the overhead, if any, that C++ may have over C, when structs are used. An opinion I have heard is that classes have some overhead that structs don't, in C++, but I question this. ...
When you have a complex property, should you instantiate it or leave it to the user to instantiate it? For example (C#) A) class Xyz{ List<String> Names {get; set;} } When I try to use, I have to set it. ... Xyz xyz = new Xyz(); xyz.Name = new List<String>(); xyz.Name.Add("foo"); ... Where as if I modify the code B) cla...
I'm trying to find a way to determine how many parameters a constructor has. Now I've built one constructor with no parameters and 1 constructor with 4 parameters. Is there, in C#, a way to find out how many parameters a used or given constructor has? Thing is, I'm using a third constructor to read log files. These logs files are read...
Can an abstract class have a constructor? If so, how it can be used and for what purposes? ...
class C { T a; public: C(T a): a(a) {;} }; Is it legal? ...
I have a not-so-small class under development (that it changes often) and I need not to provide a public copy constructor and copy assignment. The class has objects with value semantics, so default copy and assignment work. the class is in a hierarchy, with virtual methods, so I provide a virtual Clone() to avoid slicing and to perform ...
I am implementing a class to compare directory trees (in C#). At first I implemented the actual comparison in the class's constructor. Like this: DirectoryComparer c = new DirectoryComparer("C:\\Dir1", "C:\\Dir2"); But it doesn't feel "right" to do a possible lengthy operation in the constructor. An alternative way is to make the cons...
I have a code: class AbstractQuery { virtual bool isCanBeExecuted()=0; public: AbstractQuery() {} virtual bool Execute()=0; }; class DropTableQuery: public AbstractQuery { vector< std::pair< string, string> > QueryContent; QueryValidate qv; public: explicit DropTableQuery(const string& qr): AbstractQuery(), qv(q...
I'm creating an interface wrapper for a class. The member within the class is a reference(to avoid copying the large structure). If I create a private constructor, what is the best way to initialize that reference to appease the compiler? struct InterfaceWrapper { InterfaceWrapper( SomeHugeStructure& src ):m_internal(src){}; i...
Is it possible to call a constructor from another (within the same class, not from a subclass)? If yes how? And what could be the best way to call another constructor (if there are several ways to do it)? ...
Should operations that could take some time be performed in a constructor or should the object be constructed and then initialised later. For example when constructing an object that represents a directory structure should the population of the object and its children be done in the constructor. Clearly, a directory can contain director...