declare array with a default value?

[james]

Hi,

Just looking here: http://msdn2.microsoft.com/en-us/library/9b9dty7d.aspx I
can't quite see what I want to do.
I want an array of Booleans of length 102, all initially "false".
I have this so far:

public bool[] Monitors = new bool[102];

but if I add on the end of that : {false}, I get a compile error of "Invalid
rank specifier, expected ',' or ']'.
Now, I presume there is a quicker way than typing
{false,false,fa lse,false.... 100 times? :)
Or does it default to false anyway?

[Ciaran O''Donnell]

RE: declare array with a default value?

Luckily for you, booleans are false by default anyway.

Ciaran O'Donnell

"james" wrote:

Hi,
>
Just looking here: http://msdn2.microsoft.com/en-us/library/9b9dty7d.aspx I
can't quite see what I want to do.
I want an array of Booleans of length 102, all initially "false".
I have this so far:
>
public bool[] Monitors = new bool[102];
>
but if I add on the end of that : {false}, I get a compile error of "Invalid
rank specifier, expected ',' or ']'.
Now, I presume there is a quicker way than typing
{false,false,fa lse,false.... 100 times? :)
Or does it default to false anyway?
>
>
>

[coolCoder]

Re: declare array with a default value?

Hi,

Or does it default to false anyway?

You are right. When you initialize a new array of bool's all the
elements have default values set to False.


private void button1_Click(o bject sender, EventArgs e)
{

bool[] arr = new bool[3];


foreach (bool b in arr)
{
MessageBox.Show (b.ToString());
}


}

Try this code in a windows application for a button click event. You
can change the array size.

Thanks.

[james]

Re: declare array with a default value?


"coolCoder" <anant.yadunath .kulkarni@gmail .comwrote in message
news:1158925815 .307129.118910@ h48g2000cwc.goo glegroups.com.. .

Hi,
>

>Or does it default to false anyway?

>
You are right. When you initialize a new array of bool's all the
elements have default values set to False.
>
>
private void button1_Click(o bject sender, EventArgs e)
{
>
bool[] arr = new bool[3];
>
>
foreach (bool b in arr)
{
MessageBox.Show (b.ToString());
}
>
>
}
>
Try this code in a windows application for a button click event. You
can change the array size.
>

Thanks to both replies - false is handy :)
My other option was to simply loop through and set them all to false before
the *useful* stuff that will happen, but that seemed a horrible waste of cpu
cycles. A Default of false suits me fine.

James.

[Morten Wennevik]

Re: declare array with a default value?

Hi James,

All values types (int, bool etc) are set to their default level, which
usually is 0 or false. References will be null. If you want another
value you need to loop through and set it yourself.


On Fri, 22 Sep 2006 13:54:28 +0200, james <james@com.comw rote:

>
"coolCoder" <anant.yadunath .kulkarni@gmail .comwrote in message
news:1158925815 .307129.118910@ h48g2000cwc.goo glegroups.com.. .

>Hi,
>>

>>Or does it default to false anyway?

>>
> You are right. When you initialize a new array of bool's all the
>elements have default values set to False.
>>
>>
> private void button1_Click(o bject sender, EventArgs e)
> {
>>
> bool[] arr = new bool[3];
>>
>>
> foreach (bool b in arr)
> {
> MessageBox.Show (b.ToString());
> }
>>
>>
> }
>>
> Try this code in a windows application for a button click event. You
>can change the array size.
>>

>
Thanks to both replies - false is handy :)
My other option was to simply loop through and set them all to false
before
the *useful* stuff that will happen, but that seemed a horrible waste of
cpu
cycles. A Default of false suits me fine.
>
James.
>
>

--
Happy Coding!
Morten Wennevik [C# MVP]

[Noah Sham]

Re: declare array with a default value?

Hi,

In general, if you wanted to initialize your array of value types to a
specific value other than the default you would need to loop through the
array.

for (int x=0; x<Monitors.Leng th; ++x )
{
Monitors[x] = true;
}

"james" <james@com.comw rote in message
news:4513c30b$0 $2511$fa0fcedb@ news.zen.co.uk. ..

Hi,
>
Just looking here: http://msdn2.microsoft.com/en-us/library/9b9dty7d.aspx
I can't quite see what I want to do.
I want an array of Booleans of length 102, all initially "false".
I have this so far:
>
public bool[] Monitors = new bool[102];
>
but if I add on the end of that : {false}, I get a compile error of
"Invalid rank specifier, expected ',' or ']'.
Now, I presume there is a quicker way than typing
{false,false,fa lse,false.... 100 times? :)
Or does it default to false anyway?
>

[Bill Butler]

Re: declare array with a default value?

"james" <james@com.comw rote in message
news:4513c30b$0 $2511$fa0fcedb@ news.zen.co.uk. ..

Hi,
>
Just looking here:
http://msdn2.microsoft.com/en-us/library/9b9dty7d.aspx I can't quite
see what I want to do.
I want an array of Booleans of length 102, all initially "false".
I have this so far:
>
public bool[] Monitors = new bool[102];
>

Have you looked into using the BitArray class instead of an Array of
bits?

Bill

[james]

Re: declare array with a default value?


"Bill Butler" <qwerty@asdf.co mwrote in message
news:wYQQg.4194 $Bh.2872@trnddc 03...

>
Have you looked into using the BitArray class instead of an Array of bits?
>

I haven't - but I'll investigate. Presumably it's more efficient?

[Bill Butler]

Re: declare array with a default value?

"james" <james@com.comw rote in message
news:4513e3dc$0 $11779$db0fefd9 @news.zen.co.uk ...

>
"Bill Butler" <qwerty@asdf.co mwrote in message
news:wYQQg.4194 $Bh.2872@trnddc 03...

>>
>Have you looked into using the BitArray class instead of an Array of
>bits?
>>

>
I haven't - but I'll investigate. Presumably it's more efficient?

forgetting about overhead, an Array of bools takes up a whole byte for
every bit stored. It also has some constructors that ease
initialization. There are other features surrounding bit twiddling as
well.

Bill