NP54 Declaring different way

Question

Hi Guys

I wish to know is there any difference in declaring a variable in different way for example:

int x;

Same variable is declared in different way

int x = new int();

The article in the following website give rise to this question. Anyone knows please explain.

http://www.c-sharpcorner.com/UploadFile/rmcochran/csharp_memory01122006130034PM/csharp_memory.aspx

Thank you

This implimention is in the article

public int ReturnValue()
{
         int x = new int();
         x = 3;
         int y = new int();
         y = x;
         y = 4;
         return x;
}

Maha · Answer

Thank you very much for the explanation Alan

Alan · Answer

Although the 'int' type (or System.Int32 to give it its full title) has a default parameterless constructor it is seldom used because all it does is create a new int with the value of zero. So these lines do exactly the same thing: int x = 0; int x = new int(); However this line ( within a method or property ) is different: int x; What that does is create a new local 'int' variable called 'x' but no value is assigned to it. The compiler therefore regards it as unassigned until you do assign a value to it. Consequently the compiler produces an error if you try (or you appear to be trying) to use that variable without giving it a value first. On the other hand if the same line is used as the declaration of a field  rather than a local variable the compiler will allow it because (by default) all int fields are given a value of zero.