About best coding Style of C#

[kiplring]

1.
int[] intArr = new int[255];

2.
int[] intArr = new int[255];
rgnNumberArr.In itialize();

3.
int[] intArr = new int[255];
for( int i=0; i<intArr .lenght; i++)
{
intArr [i] = 0;
}

intArr allways initilized with 0 value?
or should I initialize it?

choose best code 1,2,3?

[Jon Skeet [C# MVP]]

Mark Wilden <Ma********@new sgroups.nospam> wrote:

"kiplring" <ki********@hot mail.com> wrote in message
news:11******** **************@ g10g2000cwb.goo glegroups.com.. .

1.
int[] intArr = new int[255];

2.
int[] intArr = new int[255];
rgnNumberArr.In itialize();

3.
int[] intArr = new int[255];
for( int i=0; i<intArr .lenght; i++)
{
intArr [i] = 0;
}

intArr allways initilized with 0 value?
or should I initialize it?

I think the best way to solve this problem is 1) Look up Array.Initializ e()
to see what it does, and 2) Run the code to see what it produces. Much
quicker than asking people.

Running the code doesn't actually give any guarantee, however. For
instance, if the language specification didn't say what the result of
version 1 was, it might be fine at the moment but produce bogus results
later on.

Looking up array initialization in the spec is the way forward - in
this case, it *does* specify that the new array is filled with 0s to
start with.

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

[Mark Wilden]

"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** *@msnews.micros oft.com...

Running the code doesn't actually give any guarantee, however. For
instance, if the language specification didn't say what the result of
version 1 was, it might be fine at the moment but produce bogus results
later on.

You're right, but for all practical purposes, running the code would give
you a quicker answer than posting to a newsgroup. It certainly should be
done just to see what the current behavior of the compiler is. As for
guarantees, there are others than are found in language standards - such as
Microsoft's desire not to break code which (fairly or unfairly) relies on
this behavior.

I was really just commenting on the practice of asking questions when a
better way is to do some experimentation , hit F1 in VS, or (indeed) look up
the issue in the spec. It always makes me think the questioner is trying to
short-circuit an interview question or homework assignment.

But you're right -- the -best- way to solve the problem is neither of the
methods I suggested. :)

///ark

[Mark Wilden]

"Jon Skeet [C# MVP]" <sk***@pobox.co m> wrote in message
news:MP******** *************** *@msnews.micros oft.com...

Why would you "never rely on this behaviour"? Which other pieces of
behaviour which are documented in the language specification should you
not rely on?

I hear that. It's like initializing members to null, "just to be on the safe
side."

///ark

[Andy]

> Running the code doesn't actually give any guarantee, however. For

instance, if the language specification didn't say what the result of
version 1 was, it might be fine at the moment but produce bogus results
later on.

The language speification DOES say what the result of #1 is; all ints
are initialized to 0. Check the CLS specification if you don't believe
me, but it does state that all number primitives MUST default to 0.

Andy

[Giulio Petrucci]

Ignacio Machin ( .NET/ C# MVP ) ha scritto:

Hi,

int intArrayLength = 255;
int[] intArr = new int[255];
for( int i=0; i<intArr .lenght; i++)
{
intArr [i] = 0;
}

You do not need to initialize a value type array, it will ALWAYS have a
value (contrary to what happen with a reference typed array which will be
null ), this is why a DateTime cannot be null.

I know, but I was thinking: "ok, and if tomorrow I have to change my array
length and/or change the initial values?".

Bye,
Giulio

[Jon Skeet [C# MVP]]

Andy <aj*****@alum.r it.edu> wrote:

Running the code doesn't actually give any guarantee, however. For
instance, if the language specification didn't say what the result of
version 1 was, it might be fine at the moment but produce bogus results
later on.

The language speification DOES say what the result of #1 is; all ints
are initialized to 0. Check the CLS specification if you don't believe
me, but it does state that all number primitives MUST default to 0.

That's why I wrote "*if* the language specification didn't say". I then
went on to write this bit which you snipped:

<quote>
Looking up array initialization in the spec is the way forward - in
this case, it *does* specify that the new array is filled with 0s to
start with.
</quote>

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

[kiplring]

Thanks.

Whenever the framework being bigger, the developer should memorize more
rules.

I determined NO 1 choice.

[Andy]

Ahh, sorry Jon, it was late, and I read too fast, and missed the word
if. Sorry about that.

[Jon Skeet [C# MVP]]

Giulio Petrucci <gi************ *@RIMUOVIspeech village.com> wrote:

int intArrayLength = 255;
int[] intArr = new int[255];
for( int i=0; i<intArr .lenght; i++)
{
intArr [i] = 0;
}

You do not need to initialize a value type array, it will ALWAYS have a
value (contrary to what happen with a reference typed array which will be
null ), this is why a DateTime cannot be null.

I know, but I was thinking: "ok, and if tomorrow I have to change my array
length and/or change the initial values?".

Then tomorrow you make that change. (And tomorrow you might *use* your
intArrayLength variable :) There's no point in including code which
does nothing useful just in *case* you need to change it in a way
you've predicted - it's more likely that you'll need to change it in a
way which you can't predict at this point.

Google for YAGNI for more on this :)

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

[Lau Lei Cheong]

I won't rely on behaviours that I'm not sure at the time I write something.

I search the MSDN library, but can't find anywhere explicitly say this. The
Array Overview said nothing about it too. And everywhere here and there
inside it declares variable like this:

Copied from "Properties overview" :
ms-help://MS.MSDNQTR.2006 JAN.1033/cpguide/html/cpconProperties Overview.htm

[C#]
private int number = 0;
[Visual Basic]
Private number As Integer = 0

So I think there should be a reason for initializing the variables
explicitly.

P.S.: I AM sure now. :)

"Jon Skeet [C# MVP]" <sk***@pobox.co m>
???????:MP***** *************** ****@msnews.mic rosoft.com...

Lau Lei Cheong <le****@yehoo.c om.hk> wrote:

btw, I somehow remember I've read that the .NET framework will
preinitialize
interger array to zero for you but you should never rely on this
behaviour... I'm not so sure about this...

Why would you "never rely on this behaviour"? Which other pieces of
behaviour which are documented in the language specification should you
not rely on?

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