operator new with "value type"

[carnold]

Hello,

I'm a developer coming from C++ and Java ... I've going thru
"Effective C#" (which highly recommend for people coming from other
languages wanting to learn C#), and it states that "value types" are
always created on the stack, but then showed the "creation" of one w/
operator new. I guess it makes sense, but is it true that:

MyValueType t;

and

MyValueType t = new MyValueType();

are equivalent w/ regard to where the object is stored? That just
seems odd to me. I suppose this is probably in a FAQ somewhere (I
welcome any pointers to any FAQ list that answers this), but I
couldn't find it stated obviously (tho I didn't spend too long
looking :) ...

-Charlie

[=?UTF-8?B?QXJuZSBWYWpow7hq?=]

Lew wrote:

Arne Vajhøj wrote:

>Lew wrote:

>>In fact, within FORTRAN itself there were changes within "familiar
constructs" . A loop index variable was scoped to the loop in some
dialects, but wider in others. The newer languages changed the
meaning of the familiar construct of "scope", and made it explicit,
thus fixing a lot of weird bugs.

Fortran 90/95 ?

Not possible in 66 and 77.

(I know that C++ had such a problem before ANSI standardization )

I don't remember which version of FORTRAN scoped loop variables to the
loop for you, but it was in 1980. The reason was optimization - the
loop variable could be enregistered. The register would be colored by a
different variable immediately after loop exit.

Are you sure you remember correct ?

Declarations in Fortran (at least the old versions) are always
before executable statements and therefor with subroutine/function
wide scope. I would assume that implicit declared variable would be
the same.

And AFAIK the Fortran standard explicitly define that the loop
variable to be last value + step after the do loop.

Arne

[Ben Voigt [C++ MVP]]

"Barry Kelly" <ba***********@ gmail.comwrote in message
news:q1******** *************** *********@4ax.c om...

Ben Voigt [C++ MVP] wrote:

>"Jon Skeet [C# MVP]" <sk***@pobox.co mwrote in message
news:MP******* **************@ msnews.microsof t.com...

<"Ignacio Machin \( .NET/ C# MVP \)" <machin TA laceupsolutions .com>>
wrote:
Interesting, it might be the case that I have not seen that much code
that
was not mine :)

It would be overkill to force the use of { though.

Would it really? I certainly find code much more readable that way, and
it *is* required for various constructs IIRC.

do-while and switch require the braces

---8<---
class App
{
static void Main()
{
do System.Console. WriteLine(); while(false);
}
}
--->8---

Ok, you win. I have *never* before seen a do-while without braces in either
C#, C++, or plain C.

>
C# switch does require braces, although consider C/C++:

---8<---
int main(void)
{
switch (0);
return 0;
}
--->8---

(I in no way condone use of the above forms; though I'm ambivalent about
requiring {} on if-statement sub-blocks.)

-- Barry

--
http://barrkel.blogspot.com/

[Jon Skeet [C# MVP]]

Ben Voigt [C++ MVP] <rb*@nospam.nos pamwrote:

<snip>

Ok, you win. I have *never* before seen a do-while without braces in either
C#, C++, or plain C.

I hope I never see one in production code, either :)

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
World class .NET training in the UK: http://iterativetraining.co.uk

[=?ISO-8859-1?Q?Arne_Vajh=F8j?=]

Ben Voigt [C++ MVP] wrote:

"Barry Kelly" <ba***********@ gmail.comwrote in message

> do System.Console. WriteLine(); while(false);

Ok, you win. I have *never* before seen a do-while without braces in either
C#, C++, or plain C.

Neither have I.

But considering that in Pascal you can even do multiple
statements in a repeat until loop without begin end blocks,
then it should not be that surprising.

Arne

[Barry Kelly]

Arne Vajhøj wrote:

Ben Voigt [C++ MVP] wrote:

"Barry Kelly" <ba***********@ gmail.comwrote in message

do System.Console. WriteLine(); while(false);

Ok, you win. I have *never* before seen a do-while without braces in either
C#, C++, or plain C.

Neither have I.

But considering that in Pascal you can even do multiple
statements in a repeat until loop without begin end blocks,
then it should not be that surprising.

It isn't like Pascal - in C/etc., the logic is that a *single* statement
is expected between the 'do' and the 'while', so the parser code looks
very roughly like this (in LL recursive descent):

case DO:
Skip(DO);
body = ParseStatement( );
Expect(WHILE);
// etc...

It could have been rewritten to something like:

case DO:
Skip(DO);
body = ParseBlockState ment();
Expect(WHILE);
// etc...

.... but it never has, for reasons unknown.

-- Barry

--
http://barrkel.blogspot.com/