C# Discussion Boards - CodeProject

Mycroft Holmes19-Jul-09 20:17

Mycroft Holmes

19-Jul-09 20:17

I presume you mean in Winforms.

DOCK is the property you are looking for. Your user control will have a dock property.

User the Z order (bring to front/ send to back) of the control to manage the positioning in the control hierarchy.

Never underestimate the power of human stupidity
RAH

Satish Pai19-Jul-09 21:03

Satish Pai

19-Jul-09 21:03

No i am talking abt Window, Like if u open a Drive it should have Left pane Just has same in M-Files.

Ashfield19-Jul-09 21:40

Ashfield

19-Jul-09 21:40

Which is what Mycroft was also talking about. You need to write the code to do what you need, it isn't magic.

Bob
Ashfield Consultants Ltd
Proud to be a 2009 Code Project MVP

Cubic roots of negative numbers, Math.Pow()

OriginalGriff19-Jul-09 21:50

OriginalGriff

19-Jul-09 21:50

I think you mean that you want the form divided into two panels, a left pane and a right pane? If so, then look at SplitContainer control, which does exactly that.

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Wizard

john563219-Jul-09 18:42

john5632

19-Jul-09 18:42

Hi All,

I am new to c#, I have a requirement to design a wizard in c# So please guide to do this.

Re: Wizard

N a v a n e e t h19-Jul-09 20:10

N a v a n e e t h

19-Jul-09 20:10

There are many here at CP. Have you searched? Here are few

1 - Designer centric Wizard control[^]

2 - A .NET Wizard control[^]

Smile | :)

Navaneeth

How to use google | Ask smart questions

Re: Wizard

john563219-Jul-09 23:21

john5632

19-Jul-09 23:21

Thank you but I want to create my own, don
t want to use of others control.

Please let me know how to do that?

Brandon Walton19-Jul-09 17:22

19-Jul-09 17:22

Hello everyone,

I ran into a bit of an issue with Math.Pow() today while doing some work with cubic equations. The cubic root of a real negative number, is a real negative number, correct? For some reason, when X is a negative value, Math.Pow(X, (double)1/3) returns NaN instead of a negative real number.

Hopefully I'm not forgetting something...

Any help would be appreciated, thanks.

PIEBALDconsult19-Jul-09 17:28

19-Jul-09 17:28

Huh, must not realize what you're trying to do. Maybe write your own?

The Algorithm (and Mathematics) forum may be a better place to post this.

Brandon Walton19-Jul-09 17:42

19-Jul-09 17:42

Opps, sorry if I posted in the wrong forum, it just seemed like a C# thing.

In case you didn't know, a cubic root is just like a square root (x^(1/2)). As in 2^3 = 8, 8^(1/3) = 2.

PIEBALDconsult19-Jul-09 17:53

19-Jul-09 17:53

Not the worst choice of forum.

I realize that about power and root, on the other hand, a double can't represent 1/3 precisely.

Brandon Walton19-Jul-09 18:36

19-Jul-09 18:36

It gives the correct answer if X is positive in Math.Pow(X, (double)1/3), so something weird is going on...

harold aptroot19-Jul-09 17:53

harold aptroot

19-Jul-09 17:53

Interesting problem here. Math.Pow probably (I'm not sure, but it's what I would do) uses Taylor series to calculate e^(x * ln(y)) (where ^ denotes exponentiation, and the goal is pow(x,y))
And the natural logarithm of a negative real is of course a complex, which it might not be able to handle, causing a NaN somewhere which then propagates through all further calculations to end up in the result.

This is just a theory, and I wouldn't bet anything on it, but I think it's plausible.

Brandon Walton19-Jul-09 18:22

19-Jul-09 18:22

Yeah, that sounds right. NaN seems to be the C# default for anything that would be complex.

I made a little work around which seems to work.

static public double Pow(double x, double y)
{
    return y < 1 && (1 / y) % 2 == 1 && x < 0 ? -Math.Pow(Math.Abs(x), y) : Math.Pow(x, y);
}

Though this seems really improper...

harold aptroot19-Jul-09 18:43

harold aptroot

19-Jul-09 18:43

Brandon Walton wrote:
(1 / y) % 2 == 1

This looks dangerous, equality of doubles.. well.. you've heard that before. Are you sure it's not "!= 0"?

But anyway, the default math library that comes with .NET doesn't do complex math. It's a shame, but that's how it is.. Now, I know you probably meant it the right way, so no offense, but just in case (and for completeness) : normal CPU's implement the IEEE 754 kind of math so NaNs just happen, C# can't help it (ok it could, but that would just make it terribly slow at floating point math)

Brandon Walton19-Jul-09 19:09

19-Jul-09 19:09

Ohh, I always assumed NaN were native to C#. I need to get out more...

harold aptroot wrote:
This looks dangerous, equality of doubles

Just the way I like it Cool | :cool:

. But yeah, just pretend you didn't see that.

harold aptroot wrote:
Are you sure it's not "!= 0"?

And yeah, should be != 0 Dead | X|

PIEBALDconsult19-Jul-09 18:53

19-Jul-09 18:53

I would try it normally first, then only do weird stuff if the result is NaN (or on Exception).

harold aptroot19-Jul-09 18:59

harold aptroot

19-Jul-09 18:59

Math.Pow([value smaller than 0], [non integral value]) is always NaN, according to the specs[^]
What else do you suggest?

I may be reading it wrong (nearly 7 in the morning, so I make mistakes easily), but to me it looks like you're suggesting that he do what he did already - which already proved to go wrong..

PIEBALDconsult19-Jul-09 20:48

19-Jul-09 20:48

But if it's to be a general-use routine, why not assume it will be used in the normal way and only try to add special handling as a backup?

How many times each unique String appears in the collection.

Luc Pattyn20-Jul-09 1:05

Luc Pattyn

20-Jul-09 1:05

to summarize what others have said:

1. read the doc, it lists special cases including yours:
x < 0 but not NegativeInfinity; y is not an integer, NegativeInfinity, or PositiveInfinity ==> NaN

2. realize Math.Pow is using exp(y*ln(x)) so x better be positive
(you don't have to know that, but it justifies some of the documented special cases)

3. realize (double)1/3 can't be stored exactly in binary (not really relevant here)

4. make your own cubicroot method, which performs sign(x)*Math.Pow(abs(x),y)

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

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dsrao19-Jul-09 17:14

dsrao

19-Jul-09 17:14

Hi All,

Here are the code...

//

List< String >category=new List < String >();

category.Add("House");
category.Add("Car");
category.Add("Dog");
category.Add("Car");

I want to show report like this...

Name Count
===== =====
Car 2
Dog 1
House 1

Please let me know how to do the above output.

Thanks & Regards
Rao

Re: How many times each unique String appears in the collection.

PIEBALDconsult19-Jul-09 17:16