In this case the value is null - nothing. So we say that the reference is initialized to null. Humans are born. Objects are instantiated. A baby is an instance of a Human, an object is an instance of some Class. The act of creating an instance of a Class is called instantiation Ta-Da! Three distinct things are going on above using distinct terminology and that terminology is not interchangeable :. A reference-type variable is also called simply "a reference".
A "value-type variable" is not a reference. This: "objectA is an instance of an object" is profoundly wrong. If objectA was "an instance of objectB" then it must be that objectA begins life with objectB's type - whatever that is - and current state - whatever that is. What about creating objects D, E, and F as objectB changes? Nay, nay! It is the conceptual and technical case the "objectA is an instance of a Class". I jab my finger at your code and say "this instance has an invalid property.
Maybe that's why the loop fails. You gotta validate parameters during instantiation. That's why the method call throws an exception. A reference type variable's name and value exists independently.
And I do mean independent. A variable is initialized with a value. An object is instantiated when memory is allocated for it and it's constructor has been run. This variable has not been initialized. Once I assign a value to the obj variable, the variable will be initialized. Here are examples of initialization:. Instantiation is a very different thing but is related since instantiation is usually followed by initialization:.
In the preceding line of code, the obj variable is initialized with the reference to the new Object that was instantiated. We say that the new Object was instantiated because we have created a new instance of it.
Now I believe that VB. NET makes this a lot more confusing than C because it is not clear that an assignment is taking place in the code above. In C it is much clearer that there is both an instantiation of an instance and an initialization of a variable:.
To initialize something is to set it to its initial value. To instantiate something is to create an instance of it. Since an object's constructor also sets the object's properties to their default values, it's often correct to say that instantiating an object initializes it. Misleading, if the object exposes a method that you have to explictly call to initialize it after it's instantiated, as is sometimes the case. Instantiated means that an instance of the object has been created.
Initiated means that that same object has done some initialization. When you instantiate a class or object, you're creating a new instance of it, or allocating memory to "hold" one. Initializing that object would be the instructions that are performed during instantiation. Instantiation is when you create an instance of a class. That instance is then an object, and you can set its properties, or call methods on it tell it to do things.
Initiation is when you set up a set of initial conditions for something. That something might be an object, where you tell it to initiate itself, or just a variable to which you assign a value.
An object might initialise some other things, or even instantiate other objects as part of its initiation. The difference is that instantiation is creation of a thing that can do stuff; initiation is stuff that gets done. The subject of reference or context matters. When talking in terms of variable , we use the word initialize. Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
Object initializers enable you to declare and instantiate an instance of a class in a single statement. In addition, you can initialize one or more members of the instance at the same time, without invoking a parameterized constructor.
When you use an object initializer to create an instance of a named type, the parameterless constructor for the class is called, followed by initialization of designated members in the order you specify. The following procedure shows how to create an instance of a Student class in three different ways. The class has first name, last name, and class year properties, among others. Each of the three declarations creates a new instance of Student , with property First set to "Michael", property Last set to "Tucker", and all other members set to their default values.
The result of each declaration in the procedure is equivalent to the following example, which does not use an object initializer. You can copy the code from that topic to set up the class and create a list of Student objects to work with.
NET makes this a lot more confusing than C because it is not clear that an assignment is taking place in the code above. In C it is much clearer that there is both an instantiation of an instance and an initialization of a variable:.
To initialize something is to set it to its initial value. To instantiate something is to create an instance of it. Since an object's constructor also sets the object's properties to their default values, it's often correct to say that instantiating an object initializes it.
Misleading, if the object exposes a method that you have to explictly call to initialize it after it's instantiated, as is sometimes the case.
Python Javascript Linux Cheat sheet Contact. What is the difference between "instantiated" and "initialized"?
Value vis-a-vis Reference Types Variables in C are in 1 of 2 groups. Parts of a Variable There is the variable name and its value. Two parts. Variables are Initialized All variables are always given an initial value at the point the variable is declared.
Objects are Instantiated Humans are born. Restating the facts: A reference-type variable is also called simply "a reference". DoSomething ; "You declared the variable but never assigned it. An instantiated object may or may not have a reference to it. An instantiated object may have many references to it. A declared reference may or may not be pointing to an object. For instance here is a variable: Dim obj as Object This variable has not been initialized.
Often this is the more or less same thing. Tags: Vb. Net Variables. Related Numbering polygons according to their spatial relationships?
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