#new-operator

How-to: Create an empty object in JavaScript with {} or new Object()? #development #it #dev

Create an empty object in JavaScript with {} or new Object()?

There are two different ways to create an empty object in JavaScript:

var objectA = {} var objectB = new Object()

Is there any difference in how the script engine handles them? Is there any reason to use one over the other?

Similarly it is also possible to create an empty array using different syntax:

var arrayA = [] var arrayB = new…

How to: Malloc vs new — different padding

Malloc vs new different padding

I’m reviewing someone else’s C++ code for our project that uses MPI for high-performance computing (10^5 – 10^6 cores). The code is intended to allow for communications between (potentially) different machines on different architectures. He’s written a comment that says something along the lines of:

We’d normally use new and delete, but here I’m using malloc and

Fixed Using "Object.create" instead of "new" #dev #it #asnwer

Using "Object.create" instead of "new"

Javascript 1.9.3 / ECMAScript 5 introduces Object.create, which Douglas Crockford amongst others has been advocating for a long time. How do I replace new in the code below with Object.create?

var UserA = function(nameParam) { this.id = MY_GLOBAL.nextId(); this.name = nameParam; } UserA.prototype.sayHello = function() { console.log('Hello '+ this.name); }…

How to: Why does the use of 'new' cause memory leaks?

Why does the use of ‘new’ cause memory leaks?

I learned C# first, and now I’m starting with C++. As I understand, operator new in C++ is not similar to the one in C#.

Can you explain the reason of the memory leak in this sample code?

class A { ... }; struct B { ... }; A *object1 = new A(); B object2 = *(new B());

Answer: Why does the use of ‘new’ cause memory leaks?

When creating object2you’re…

How to: When should I use the new keyword in C++?

When should I use the new keyword in C++?

I’ve been using C++ for a short while, and I’ve been wondering about the new keyword. Simply, should I be using it, or not?

1) With the new keyword…

MyClass* myClass = new MyClass(); myClass->MyField = "Hello world!";

2) Without the new keyword…

MyClass myClass; myClass.MyField = "Hello world!";

From an implementation perspective, they don’t seem that…

Fixed Passing arguments to C# generic new() of templated type #dev #it #asnwer

Passing arguments to C# generic new() of templated type

I’m trying to create a new object of type T via its constructor when adding to the list.

I’m getting a compile error: The error message is:

‘T': cannot provide arguments when creating an instance of a variable

But my classes do have a constructor argument! How can I make this work?

public static string GetAllItems(...) where T : new() {…

How to: C++: Delete this?

C++: Delete this?

Is it allowed to delete this; if the delete-statement is the last statement that will be executed on that instance of the class? Of course I’m sure that this class-instance is newly-created.

I’m thinking of something like this:

void doStuff() { // in the controller, this object is the "working module" // now, if we want to change it, like this: controller->setWorkingModule(new…

How to: C++ new int0 — will it allocate memory?

C++ new int[0] will it allocate memory?

A simple test app:

cout << new int[0] << endl;

outputs:

0x876c0b8

So it looks like it works. What does the standard say about this? Is it always legal to “allocate” empty block of memory?

Answer: C++ new int[0] will it allocate memory?

Yes, it is legal to allocate a zero-sized array like this. But you must also delete it.

Answer: C++ new int[0] will it…