Re: algorithm for 6 digits unique number - C# Discussion Boards

algorithm for 6 digits unique number

6-Dec-05 1:51

ambedkar wrote:
how to create a dll file.

Create a Class Library project

ambedkar wrote:
where, and how it is used?

A DLL is, in .NET, a type of assembly that is usually a Class Library. Code behind for ASP.NET applications compile to DLL files.

It is used to hold libraries of code. For example, The business logic of an application may be put in a DLL in order to separate it from the user interface. A set of custom controls may be put in a DLL. Test fixtures are normally placed in a separate DLL from the set of classes that they test.

Basically, any code that is invoked from somewhere else.

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Ronen Tidhar6-Dec-05 1:12

Ronen Tidhar

6-Dec-05 1:12

Is anyone has an idea how do I generate 6 digits unique number for the same day. (Based on time ?!) The number should be milliseconds difference.

10x
TD

Colin Angus Mackay6-Dec-05 1:19

6-Dec-05 1:19

Ronent wrote:
how do I generate 6 digits unique number for the same day

same day as what? To what is the day in comparison?

Confused | :confused:

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J4amieC6-Dec-05 2:25

J4amieC

6-Dec-05 2:25

A quick check of the number of milliseconds in a day gives 86400000

TimeSpan ts = new TimeSpan(1,0,0,0,0);<br />
Console.WriteLine(ts.TotalMilliseconds);

So, first point you are not going to be able to generate a unique 6 digit number, that is millisecond different, based on the current millisecond in a given day.

Lets see how accurate it could be....

Max 6 digit number = 999999
Milliseconds in a day = 86400000
Spread = 86400000 / 999999 = 86.4ms (approx)

So every 86.4ms (thats 0.086 seconds) a new number would be generated, every call to generate a number within that timespan would create the same number.

Now, your choices

1) If your app will never make a call to generate this number as frequently as every 100ms, you are free to use the above solution. Just get the current number of miiliseconds since midnight, divide by (approx - do the math) 86.4, round to the nearest integer and you will have a 6 digit whole number.

2) If you DO actually need this accurate within 1ms (which i doubt) you can use a bigger number (Milliseconds is usually depicted as an int).

Ronen Tidhar7-Dec-05 1:07

Ronen Tidhar

7-Dec-05 1:07

10x a lot

I guess that's very close to what I need

Ronen Tidhar7-Dec-05 1:51

Ronen Tidhar

7-Dec-05 1:51

J4amieC hi,

I used your idea and by using Hexadecimal format,
I succeed to reduce it to 8 milisecond.

decimal i = (decimal)(new TimeSpan(1,0,0,0,0).TotalMilliseconds / 9999999);
DateTime d = DateTime.Now;
TimeSpan timeSpan = d.Subtract(new DateTime(d.Year, d.Month, d.Day));
double ml = timeSpan.TotalMilliseconds;
int ii = (int)((decimal)ml / i);
Console.WriteLine("ii=" + ii.ToString("X"));

10x
TD

Dan Neely7-Dec-05 2:09

Dan Neely

7-Dec-05 2:09

You've done your math backwards. with 86.4M values generated/day and a need for only 1M values needed/day, you've got ~86 potential values for each needed one. .net timers aren't accurate to single ms values though, I saw (but don't recall where) a comparison chart of timing methods, which ranged from ~10-50ms precision.

Are parameter arrays CLS compliant?

Nick Hounsome8-Dec-05 22:40

Nick Hounsome

8-Dec-05 22:40

The simple way to work this is to store the last number given and 'lie' a bit if the requests for numbers come too frequently:

x = timeInMS/100;  // 6 digits 
if( x== last )
  ++x;
last = x;

This gaurantees uniqueness but will occasionally give the wrong time in circumstances that cannot be avoided

Note that if the ++x is common then want you want is impossible anyway.

P.S. I haven't used hex encoding in this but why stop at base16? Use base64 and get greater precision

Nish Nishant6-Dec-05 1:02

Nish Nishant

6-Dec-05 1:02

As in subject.
Thanks in advance.

Regards,
Nish

Re: Are parameter arrays CLS compliant?

S. Senthil Kumar6-Dec-05 1:22

S. Senthil Kumar

6-Dec-05 1:22

Yes, if the VC# compiler is to be believed. This code compiles fine on my machine

[assembly:CLSCompliant(true)]
namespace ConsoleApplication1
{
    [CLSCompliantAttribute(true)]
    public class Program
    {
        public void Method(params object[] x)
        {
        }

        static void Main(string[] args) { }
    }
}

[EDIT]
Brad Abrams[^] has this to say when discussing params,

"Do not use the VarArgs calling convention, otherwise known as the ellipsis (…), exclusively because the Common Language Specification does not support it[3]."

So yes, params is CLS compliant. Interestingly, the params keyword simply seems to make the C# compiler wrap the arguments in an object array and pass it to the callee. In fact, the params thing just seems to generate an attribute for that parameter in IL, probably for use in reflection.

Regards
Senthil
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-- modified at 7:44 Tuesday 6th December, 2005

Re: Are parameter arrays CLS compliant?

Nish Nishant6-Dec-05 2:32

Nish Nishant

6-Dec-05 2:32

Thanks Senthil.

S. Senthil Kumar wrote:
Interestingly, the params keyword simply seems to make the C# compiler wrap the arguments in an object array and pass it to the callee. In fact, the params thing just seems to generate an attribute for that parameter in IL, probably for use in reflection.

Yep, that's what prompted my question. It's not directly supported in IL, and is implemented using a custom attribute on the parameter. And the calling code is always converted to using an array.

DataTime

papa19806-Dec-05 0:55

6-Dec-05 0:55

Hi to everybody.
My problem is simple how to make some label to be refresh every second?
bye best regards

Colin Angus Mackay6-Dec-05 1:17

6-Dec-05 1:17

papa1980 wrote:
My problem is simple how to make some label to be refresh every second?

If this is a win forms application then you can drop a timer on to the form and create an event handler for its, if I remember, Tick event. In your tick event handler you can update the label.

If this is for a web application you would need some javascript to do this.

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papa19806-Dec-05 1:23

6-Dec-05 1:23

thank you i will try it

papa19806-Dec-05 1:27

6-Dec-05 1:27

but how to call to this timer???

Colin Angus Mackay6-Dec-05 1:44

6-Dec-05 1:44

If you look in the documentation[^] it gives you an example.

There is also an article in MSDN Magazine comparing the different types of timers available in .NET: http://msdn.microsoft.com/msdnmag/issues/04/02/TimersinNET/[^]

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-- modified at 7:45 Tuesday 6th December, 2005

papa19806-Dec-05 1:56

6-Dec-05 1:56

I find it and make it but i don't know why when i refresh my screen is view some black line it is not look well how i can repair it???

Colin Angus Mackay6-Dec-05 2:11

6-Dec-05 2:11

papa1980 wrote:
I find it and make it but i don't know why when i refresh my screen is view some black line it is not look well how i can repair it???

Thats a new one on me. I've never heard of that happening. Remember that the timer component is a non-visual component, so it won't show up on your form. Instead it will show up on your form designer in a separate area underneath the form - this will not affect how the form is displayed.

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papa19806-Dec-05 3:48

6-Dec-05 3:48

No i mean that when i refresh some control in case label is happen some like vibrating i can't explain it exacly but when is refesh the screen you see some black line.May be the problem is that i give invaliddata() and i don't give some rectangle area????