Instantiation is the process of creating objects from a class in most object oriented and object based languages. In the C++ language, instantiation is the process of creating a class or function from a class template or function template.
Questions tagged [instantiation]
2609 questions
25
votes
3 answers
Scala 2.10, its impact on JSON libraries and case class validation/creation
In Scala 2.10 apparently we're getting improved reflection.
How will this impact lift-json, jerkson, sjson and friends? Furthermore, can we expect in the not too distant future a built-in JSON language feature a la Groovy's excellent GSON in…
virtualeyes
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24
votes
2 answers
PMD: Avoid instantiating new objects inside loops
I've got an issue with the PMD rule Avoid instantiating new objects inside loops. Here is some example code:
import java.awt.Dimension;
public class PMDDemo {
public static void main(final String[] args) {
final Dimension[] arr = new…
brimborium
- 9,362
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24
votes
4 answers
Profiling template metaprogram compilation time
I'm working on a C++ project with extensive compile-time computations. Long compilation time is slowing us down. How might I find out the slowest parts of our template meta-programs so I can optimize them? (When we have slow runtime computations,…
idupree
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23
votes
4 answers
How to instantiate a class in Objective-C that don't inherit from NSObject
Given this:
Person.h:
@interface Person
{
}
- (void) sayHello;
@end
Person.m:
#import "Person.h"
@implementation Person
- (void)sayHello
{
printf("%s", "Steve");
}
@end
How do you instantiate the Person? I tried this:
Person *p =…
Hao
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23
votes
2 answers
How to instantiate an object in TypeScript by specifying each property and its value?
Here's a snippet in which I instantiate a new content object in my service:
const newContent = new Content(
result.obj.name
result.obj.user.firstName,
result.obj._id,
result.obj.user._id,
);
The problem is that this way of…
YSA
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23
votes
5 answers
Avoid instantiating a class in java
Recently I've faced a question : How to avoid instantiating a Java class?
However, I answered by saying:
If you don't want to instantiate a class, use "abstract" modifier. Ex: javax.servlet.HttpServlet, is declared as abstract(though none of its…
jai
- 21,519
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22
votes
2 answers
Swift: Creating an Array with a Default Value of distinct object instances
I noticed a bit weird (and dangerous IMHO) behavoir in Creating an Array with a Default Value. As stated in Swift 2.1: Collection Types
Swift’s Array type also provides an initializer for creating an array of a certain size with all of its values…
Franco Rondini
- 10,841
- 8
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- 77
21
votes
2 answers
Inline object instantiation and transformation in Java
I have come to Java from Visual Basic, and seem to think I have been, in many ways, spoiled :p
Is there a way to instantiate an object and modify it inline? Something like:
JFrame aFrame = new JFrame();
aFrame.add(new JPanel() {.setSize(100,100)…
GCon
- 1,397
- 3
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21
votes
2 answers
Why do Object.create() and new Object() evaluate to different prototypes?
Why do these 2 implementations behave differently? What exactly sets them apart when it comes to evaluating their prototypes?
Creating an object with the prototype specified:
function Foo() {}
// creates an object with a specified prototype
…
shmuli
- 5,086
- 4
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- 64
21
votes
2 answers
How is a template instantiated?
It's an exercise from C++ Primer 5th Edition:
Exercise 16.27: For each labeled statement explain what, if any,
instantiations happen. If a template is instantiated, explain why; if
not, explain why not. P.677
template class Stack…
Yue Wang
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21
votes
2 answers
Exporting STL class from DLL - why is there no warning from the return type?
My question is related to exporting a C++ class with STL inside. For example:
class __declspec(dllexport) Hello
{
std::string name;
public:
std::string& getName();
void setName(const std::string& name);
}
Various articles…
xpirle
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- 6
21
votes
5 answers
Instantiating C++ lambda by its type
I want a way to make functor from function. Now I trying to wrap function call by lambda function and instantiate it later. But compiler says than lambda constructor is deleted.
So is there any way to compile this code ? Or maybe another way for…
andigor
- 722
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- 17
20
votes
3 answers
Class 'Room' is abstract; cannot be instantiated
I have an abstract class Room which has subclasses Family and Standard.
I have created room = new ArrayList(); within a Hostel class and a method to add a room to the ArrayList;
public String addRoom(String roomNumber, boolean ensuite)
{
…
Darren Burgess
- 4,200
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20
votes
5 answers
Instantiating object from inside the main of that class in Java
I was looking through my OOP class documentation and I found this example:
class Student {
private String name;
public int averageGrade;
public Student(String n, int avg) {
name = n;
averageGrade = avg;
}
…
Mihai Neacsu
- 2,045
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20
votes
5 answers
Composing a Controller class with Dependency Injection in PHP
How to solve the problem of composing a Controller class in PHP, which should be:
easily testable by employing Dependency Injection,
provide shared objects for end programmer
provide a way to load new user libraries
Look down, for controller…
Juraj Blahunka
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