Hi, I am working with classes and object class structure, but not at a complex level – just classes and functions, then, in one place, instantiation. As to __construct and __destruct, please tell me very simply: what is the purpose of constructors and destructors? I know the school level theoretical explanation, but i am expecting som...
This is the way I get to prevent funA,funB,funC, etc.. for being used before init #define INIT_KEY 0xC0DE //any number except 0, is ok static int initialized=0; int Init() { //many init task initialized=INIT_KEY; } int funA() { if (initialized!=INIT_KEY) return 1; //.. } int funB() { if (initialized!=INIT_KEY) return 1; //....
I found some sample code from here. static UIImage *backgroundImageDepressed; /** * */ @implementation DecimalPointButton + (void) initialize { backgroundImageDepressed = [[UIImage imageNamed:@"decimalKeyDownBackground.png"] retain]; } is it something like this - +(void) initialize method initialize static variables of a class...
Hi, How would I go about writing a constructor for an inner class which is implementing an interface? I know I could make a whole new class, but I figure there's got to be a way to do something along the line of this: JButton b = new JButton(new AbstractAction() { public AbstractAction() { super("This is a button"); ...
Java is complaining! cannot find symbol symbol : constructor Bar() location: class Bar JPanel panel = new Bar(); ^ QUESTION: Why am I getting this error?...everything seems to be correct. this is the coding: public class JFrameWithPanel { public static void main(String[] args) { ...
i wrote this code: class A { public: A(){d=2.2;cout<<d;} A(double d):d(d){cout<<d;} double getD(){return d;} private: double d; }; class Bing { public: Bing(){a=A(5.3);} void f(){cout<<a.getD();} private: A a; }; int main() { Bing b; b.f(); } i get the output: 2.2 5.3 5.3 instead of 5.3 5.3....
Possible Duplicate: What is the lifetime of a static variable in a C++ function? Say we have a code like this: Some class { Some() { // the ctor code } }; Some& globalFunction() { static Some gSome; return gSome; } When exactly 'the ctor code' is executed? As for normal static variables before main() or at the momen...
Is it possible to close a form while the constructor is executing (or simply to stop it showing at this stage)? I have the following code: public partial class MyForm : Form { public MyForm() { if (MyFunc()) { this.Close(); } } } Which errors in Main(), here: ...
My question is rather simple, but I am stuck. How can I choose the desired constructor from base class? // node.h #ifndef NODE_H #define NODE_H #include <vector> // definition of an exception-class class WrongBoundsException { }; class Node { public: ... Node(double, double, std::vector<double>&) throw (WrongBoun...
Example 1: SomeObject someObject = new SomeObject(); if (someObject.Method()) { //do stuff } //someObject is never used again vs Example 2: if (new SomeObject().Method()) { //do stuff } Is there any benefit to using the first method over the second, or vice versa? ...
class Base { public: Base() {} void Foo(int x) {...} }; class Derived : public Base { public: Derived(int args) { /* process args in some way */ Foo(result); } }; Is it allowed to call a method of the base class in the constructor of the derived class? I would imagine this is fine as the Base ...
Based on my question - take the following code: class Nevermore60Customer: GenericCustomer { public Nevermore60Customer(string name, string referrerName) : base (name) { this.referrerName = referrerName; } private string referrerName; private uint highCostMinutesUsed; To me, it appears the variable ...
class X { int i; public: X(int m) : i(m) {}; X(const X } const X opearator++(X X b(a.i); a.i++; return b; } void f(X a) { } }; int main() { X a(1); f(a); a++; return 0; } Here when function 'f' is called copy constructor is getting called as expected. In case of a++, operator++ functio...
The MFC's root object CObject's copy constructor and assignment are disabled by default. In MSDN, there is a description The standard C++ default class copy constructor does a member-by-member copy. The presence of the private CObject copy constructor guarantees a compiler error message if the copy constructor of your cl...
Hi everyone, Ive looked and tried but I can't find an answer. In PHP, is it possible to call a class' member function (when that class requires a constructor to receive parameters) without instantiating it as an object? A code example (which gives errors): <?php class Test { private $end=""; function __construct($value) {...
Coming from a C background, I've always assumed the POD types (eg ints) were never automatically zero-initialized in C++, but it seems this was plain wrong! My understanding is that only 'naked' non-static POD values don't get zero-filled, as shown in the code snippet. Have I got it right, and are there any other important cases that I'...
Hi, I have in my header "Test.h" a variable of a class that doesn't have a constructor without arguments. And I have a constructor like this: Test::Test() // <-- Here he complains: // error: no matching function for call to ‘Beer::Beer()’ { int i = 2; theVar = Beer(1, i); // Beer(int, int) is the only constructor } ...
The constructors of globally declared classes are invoked before main is entered. While this can be confusing to a new reader of the code because it is done so infrequently, is it necessarily a bad idea? ...
I'm reading about constructors, When an object is instantiated for a class, c'tors (if explicitly written or a default one) are the starting points for execution. My doubts are is a c'tor more like the main() in C Yes i understand the point that you can set all the default values using c'tor. I can also emulate the behavior by writ...
What is the correct way to forward all of the parent's constructors in C++0x? I have been doing this: class X: public Super { template<typename... Args> X(Args&&... args): Super(args...) {} }; ...