Variable Declaration

[Vasanth TT]

Guys,

Please help me by answering my questions. Thanks in advance

1. What is the difference between below two declaration statements

int i; i=20;
and
int i=new int(); i=20;
2. String is a class. But why its not declared using "new" keyword?

-Vasanth TT

[Andy]

On May 16, 9:07 am, Vasanth TT <[e-mail]:

1. What is the difference between below two declaration statements

int i; i=20;
and
int i=new int(); i=20;

They are both the same, although its odd to see the second form.

2. String is a class. But why its not declared using "new" keyword?

It can be:
string x = new string();

The compiler is smart enough to change:
string x = "My string";
to
string x = new string( "My string" );

[Jon Skeet [C# MVP]]

On May 16, 2:22 pm, Andy <[e-mail]:

On May 16, 9:07 am, Vasanth TT <[e-mail]:

1. What is the difference between below two declaration statements

int i; i=20;
and
int i=new int(); i=20;

They are both the same, although its odd to see the second form.

Indeed - basically the first value is ignored.

2. String is a class. But why its not declared using "new" keyword?

It can be:
string x = new string();

Except that string doesn't have a parameterless constructor ;)

The compiler is smart enough to change:
string x = "My string";
to
string x = new string( "My string" );

Not quite - new always (or at least should always) return a new
object, whereas string literals are interned. So if you do:

string x = "hello";
string y = "hello";

then x and y both refer to the same object, which they wouldn't if the
"new" operator were used.

Jon

[Moty Michaely]

On May 16, 6:52 pm, "Jon Skeet [C# MVP]" <[e-mail]:

On May 16, 2:22 pm, Andy <[e-mail]:

On May 16, 9:07 am, Vasanth TT <[e-mail]:

1. What is the difference between below two declaration statements

int i; i=20;
and
int i=new int(); i=20;

They are both the same, although its odd to see the second form.

Indeed - basically the first value is ignored.

2. String is a class. But why its not declared using "new" keyword?

It can be:
string x = new string();

Except that string doesn't have a parameterless constructor ;)

The compiler is smart enough to change:
string x = "My string";
to
string x = new string( "My string" );

Not quite - new always (or at least should always) return a new
object, whereas string literals are interned. So if you do:

string x = "hello";
string y = "hello";

then x and y both refer to the same object, which they wouldn't if the
"new" operator were used.

Jon

Yes, Jon is right. It's just the same as in Java.

BTW it's true for all literals.

Event if I do string x = new string("hello");

It will refer to the same object.

Cheers,
Moty

[Jon Skeet [C# MVP]]

Moty Michaely <Mo*****@gmail.comwrote:

Yes, Jon is right. It's just the same as in Java.

BTW it's true for all literals.

Event if I do string x = new string("hello");

It will refer to the same object.

Well, that won't compile in C# (there's no string constructor taking
just a string parameter), and in Java it *won't* refer to the same
object. Here's the code to prove my point for Java:

public class Test
{
public static void main (String[] args)
{
String x = new String("hello");
String y = new String("hello");
System.out.println (x==y);
}
}

Run it and it prints "false".

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[Vasanth TT]

What is the feedback for this answer given in this blog
http://cognitionspot.blogspot.com/
On May 16, 11:12 pm, Jon Skeet [C# MVP] <[e-mail]:

Moty Michaely <[e-mail]:

Yes, Jon is right. It's just the same as in Java.

BTW it's true for all literals.

Event if I do string x = new string("hello");

It will refer to the same object.

Well, that won't compile in C# (there's no string constructor taking
just a string parameter), and in Java it *won't* refer to the same
object. Here's the code to prove my point for Java:

public class Test
{
public static void main (String[] args)
{
String x = new String("hello");
String y = new String("hello");
System.out.println (x==y);
}

}

Run it and it prints "false".

--
Jon Skeet - <[e-mail]>http://www.pobox.com/~skeet Blog:http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too

[Vasanth TT]

http://cognitionspot.blogspot.com/20...claration.html