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

[Ignacio Machin \( .NET/ C# MVP \)]

Hi,
--
Ignacio Machin
http://www.laceupsolutions.com
Mobile & warehouse Solutions.
"Jon Skeet [C# MVP]" <sk***@pobox.co mwrote in message
news:e81c0e05-37c1-4cbb-9495-

(One slight pity about the C# 3 spec is that in one place where it
shows how C# has removed a common source of C++ errors, it uses an if
without braces - demonstrating how a completely different source of C+
+ errors is still alive and kicking in C#!)

I have never seem that error, have you?

[Jon Skeet [C# MVP]]

<"Ignacio Machin \( .NET/ C# MVP \)" <machin TA laceupsolutions .com>>
wrote:

>(One slight pity about the C# 3 spec is that in one place where it
shows how C# has removed a common source of C++ errors, it uses an
if without braces - demonstrating how a completely different source
of C++ errors is still alive and kicking in C#!)

I have never seem that error, have you?

Yes, I have. Basically code which ended up reading:

if (someExpression )
FirstStatement( );
SecondStatement ();

but should have read:

if (someExpression )
{
FirstStatement( );
SecondStatement ();
}

Not my code, of course, but I a bug I fixed :)

--
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

[Ben Voigt [C++ MVP]]

"Jon Skeet [C# MVP]" <sk***@pobox.co mwrote in message
news:MP******** *************@m snews.microsoft .com...

<"Ignacio Machin \( .NET/ C# MVP \)" <machin TA laceupsolutions .com>>
wrote:

>>(One slight pity about the C# 3 spec is that in one place where it
shows how C# has removed a common source of C++ errors, it uses an
if without braces - demonstrating how a completely different source
of C++ errors is still alive and kicking in C#!)

>I have never seem that error, have you?

Yes, I have. Basically code which ended up reading:

if (someExpression )
FirstStatement( );
SecondStatement ();

but should have read:

if (someExpression )
{
FirstStatement( );
SecondStatement ();
}

Not my code, of course, but I a bug I fixed :)

python programmers...

>
--
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?=]

Jon Skeet [C# MVP] wrote:

<"Ignacio Machin \( .NET/ C# MVP \)" <machin TA laceupsolutions .com>>
wrote:

>>(One slight pity about the C# 3 spec is that in one place where it
shows how C# has removed a common source of C++ errors, it uses an
if without braces - demonstrating how a completely different source
of C++ errors is still alive and kicking in C#!)

>I have never seem that error, have you?

Yes, I have. Basically code which ended up reading:

if (someExpression )
FirstStatement( );
SecondStatement ();

but should have read:

if (someExpression )
{
FirstStatement( );
SecondStatement ();
}

Not my code, of course, but I a bug I fixed :)

It must have happen hundred of thousands of times.

The programmer writes:

if (someExpression )
SecondStatement ();

He figure out that he does not need the { } because it is only
one statement.

Then later another statement has to be added and because it is a bit
hectic at the time then it end up as:

if (someExpression )
FirstStatement( );
SecondStatement ();

And suddenly some things stop working.

Arne

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

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 )

Arne

[Ignacio Machin \( .NET/ C# MVP \)]

Hi,
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.

"Arne Vajhøj" <ar**@vajhoej.d kwrote in message
news:47******** *************** @news.sunsite.d k...

Jon Skeet [C# MVP] wrote:

> <"Ignacio Machin \( .NET/ C# MVP \)" <machin TA laceupsolutions .com>>
wrote:

>>>(One slight pity about the C# 3 spec is that in one place where it
shows how C# has removed a common source of C++ errors, it uses an if
without braces - demonstrating how a completely different source of C++
errors is still alive and kicking in C#!)

>>I have never seem that error, have you?

Yes, I have. Basically code which ended up reading:

if (someExpression )
FirstStatement( );
SecondStatement ();

but should have read:

if (someExpression )
{
FirstStatement( );
SecondStatement ();
}

Not my code, of course, but I a bug I fixed :)

It must have happen hundred of thousands of times.

The programmer writes:

if (someExpression )
SecondStatement ();

He figure out that he does not need the { } because it is only
one statement.

Then later another statement has to be added and because it is a bit
hectic at the time then it end up as:

if (someExpression )
FirstStatement( );
SecondStatement ();

And suddenly some things stop working.

Arne

[Jon Skeet [C# MVP]]

<"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.

I use them everywhere, and haven't found any disadvantages to it.

--
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

[Ben Voigt [C++ MVP]]

"Jon Skeet [C# MVP]" <sk***@pobox.co mwrote in message
news:MP******** *************@m snews.microsoft .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

>
I use them everywhere, and haven't found any disadvantages to it.

--
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

[Barry Kelly]

Ben Voigt [C++ MVP] wrote:

"Jon Skeet [C# MVP]" <sk***@pobox.co mwrote in message
news:MP******** *************@m snews.microsoft .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---

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/

[Lew]

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.

--
Lew