VB.NET Random / C++ rnd

[Nick]

Hi there,

I'm trying to create a random number via a seed in VB.NET and C++, 2
different applications. I want to be able to use the same seed and get the
same random number but unfortunately VB.NET's Random class produces a
different set of results than the C++ rnd function.

I can't see any reference of rnd being used via API declarations and am just
trying to find a way of generating a random number via seed that is
identical in both languages. Of course I could create a C++ DLL to do it
for me and use it in the VB app, but i'd rather not go to that extreme for 1
method.

Any suggestions would be greatly appreciated!

Nick.

[Michael D. Ober]

Re: VB.NET Random / C++ rnd

"Nick" <a@a.comwrote in message
news:%23ju3Sp79 IHA.3884@TK2MSF TNGP05.phx.gbl. ..

Hi there,
>
I'm trying to create a random number via a seed in VB.NET and C++, 2
different applications. I want to be able to use the same seed and get
the same random number but unfortunately VB.NET's Random class produces a
different set of results than the C++ rnd function.
>
I can't see any reference of rnd being used via API declarations and am
just trying to find a way of generating a random number via seed that is
identical in both languages. Of course I could create a C++ DLL to do it
for me and use it in the VB app, but i'd rather not go to that extreme for
1 method.
>
Any suggestions would be greatly appreciated!
>
Nick.

If you are using managed C++ (C++/CLI), you can use the Random class in both
VB.Net and C++.

Mike.

[Gillard]

Re: VB.NET Random / C++ rnd

be happy to have a different set of result :

if not why would it be called random ?

"Michael D. Ober" <obermd.@.alum. mit.edu.nospam. wrote in message
news:JaWdnSzVr7 bFDATVnZ2dnUVZ_ uLinZ2d@earthli nk.com...

"Nick" <a@a.comwrote in message
news:%23ju3Sp79 IHA.3884@TK2MSF TNGP05.phx.gbl. ..

>Hi there,
>>
>I'm trying to create a random number via a seed in VB.NET and C++, 2
>different applications. I want to be able to use the same seed and get
>the same random number but unfortunately VB.NET's Random class produces a
>different set of results than the C++ rnd function.
>>
>I can't see any reference of rnd being used via API declarations and am
>just trying to find a way of generating a random number via seed that is
>identical in both languages. Of course I could create a C++ DLL to do it
>for me and use it in the VB app, but i'd rather not go to that extreme
>for 1 method.
>>
>Any suggestions would be greatly appreciated!
>>
>Nick.

If you are using managed C++ (C++/CLI), you can use the Random class in
both VB.Net and C++.
>
Mike.
>
>

[Nick]

Re: VB.NET Random / C++ rnd

Hi Mike,

It's not unfortunately, it's C++ / WTL, no managed code in sight
otherwise I wouldn't have this issue in the first place.

Nick.

"Michael D. Ober" <obermd.@.alum. mit.edu.nospam. wrote in message
news:JaWdnSzVr7 bFDATVnZ2dnUVZ_ uLinZ2d@earthli nk.com...

"Nick" <a@a.comwrote in message
news:%23ju3Sp79 IHA.3884@TK2MSF TNGP05.phx.gbl. ..

>Hi there,
>>
>I'm trying to create a random number via a seed in VB.NET and C++, 2
>different applications. I want to be able to use the same seed and get
>the same random number but unfortunately VB.NET's Random class produces a
>different set of results than the C++ rnd function.
>>
>I can't see any reference of rnd being used via API declarations and am
>just trying to find a way of generating a random number via seed that is
>identical in both languages. Of course I could create a C++ DLL to do it
>for me and use it in the VB app, but i'd rather not go to that extreme
>for 1 method.
>>
>Any suggestions would be greatly appreciated!
>>
>Nick.

If you are using managed C++ (C++/CLI), you can use the Random class in
both VB.Net and C++.
>
Mike.
>
>

[Nick]

Re: VB.NET Random / C++ rnd

Hi Gillard,

LOL! Unfortunately that's not quite how it works, otherwise there would
be no point in a random seed.

Nick.

"Gillard" <gillard_george s@@@@@@@@@hotma il.comwrote in message
news:%23yolsx79 IHA.5404@TK2MSF TNGP04.phx.gbl. ..

be happy to have a different set of result :
>
if not why would it be called random ?
>
"Michael D. Ober" <obermd.@.alum. mit.edu.nospam. wrote in message
news:JaWdnSzVr7 bFDATVnZ2dnUVZ_ uLinZ2d@earthli nk.com...

>"Nick" <a@a.comwrote in message
>news:%23ju3Sp7 9IHA.3884@TK2MS FTNGP05.phx.gbl ...

>>Hi there,
>>>
>>I'm trying to create a random number via a seed in VB.NET and C++, 2
>>different applications. I want to be able to use the same seed and get
>>the same random number but unfortunately VB.NET's Random class produces
>>a different set of results than the C++ rnd function.
>>>
>>I can't see any reference of rnd being used via API declarations and am
>>just trying to find a way of generating a random number via seed that is
>>identical in both languages. Of course I could create a C++ DLL to do
>>it for me and use it in the VB app, but i'd rather not go to that
>>extreme for 1 method.
>>>
>>Any suggestions would be greatly appreciated!
>>>
>>Nick.

>If you are using managed C++ (C++/CLI), you can use the Random class in
>both VB.Net and C++.
>>
>Mike.
>>
>>

[Mick Doherty]

Re: VB.NET Random / C++ rnd

Does 'Microsoft.Visu alBasic.VBMath. Rnd' produce the same results as your C++
rnd() method?

--
Mick Doherty

http://www.dotnetrix.co.uk/nothing.html

"Nick" <a@a.comwrote in message
news:#ju3Sp79IH A.3884@TK2MSFTN GP05.phx.gbl...

Hi there,
>
I'm trying to create a random number via a seed in VB.NET and C++, 2
different applications. I want to be able to use the same seed and get
the same random number but unfortunately VB.NET's Random class produces a
different set of results than the C++ rnd function.
>
I can't see any reference of rnd being used via API declarations and am
just trying to find a way of generating a random number via seed that is
identical in both languages. Of course I could create a C++ DLL to do it
for me and use it in the VB app, but i'd rather not go to that extreme for
1 method.
>
Any suggestions would be greatly appreciated!
>
Nick.
>

[Nick]

Re: VB.NET Random / C++ rnd

Hi Mick,

Unfortunately not,

Microsoft.Visua lBasic.VBMath.R andomize(871)
Dim pIntAsciiCode As Integer
pIntAsciiCode = Rnd()

Result = 1, presumably due to rounding.

...

srand(871);
int pIntAsciiCode = 0;
pIntAsciiCode = rand();

Result = 2882

...

Hmm this isn't looking good really, a whole DLL to expose 1 method! :(
:( :(

Nick.


"Mick Doherty"
<EXCHANGE#WITH@ AND.REMOVE.SQUA REBRACKETS.[mdaudi100#ntlwo rld.com]wrote in
message news:u1BuNq89IH A.1192@TK2MSFTN GP05.phx.gbl...

Does 'Microsoft.Visu alBasic.VBMath. Rnd' produce the same results as your
C++ rnd() method?
>
--
Mick Doherty

http://www.dotnetrix.co.uk/nothing.html

>
>
"Nick" <a@a.comwrote in message
news:#ju3Sp79IH A.3884@TK2MSFTN GP05.phx.gbl...

>Hi there,
>>
>I'm trying to create a random number via a seed in VB.NET and C++, 2
>different applications. I want to be able to use the same seed and get
>the same random number but unfortunately VB.NET's Random class produces a
>different set of results than the C++ rnd function.
>>
>I can't see any reference of rnd being used via API declarations and am
>just trying to find a way of generating a random number via seed that is
>identical in both languages. Of course I could create a C++ DLL to do it
>for me and use it in the VB app, but i'd rather not go to that extreme
>for 1 method.
>>
>Any suggestions would be greatly appreciated!
>>
>Nick.
>>

>

[Nick]

Re: VB.NET Random / C++ rnd

I'm just looking at the Rnd method in Reflector and very different from the
C version unfortunately :(

"Mick Doherty"
<EXCHANGE#WITH@ AND.REMOVE.SQUA REBRACKETS.[mdaudi100#ntlwo rld.com]wrote in
message news:u1BuNq89IH A.1192@TK2MSFTN GP05.phx.gbl...

Does 'Microsoft.Visu alBasic.VBMath. Rnd' produce the same results as your
C++ rnd() method?
>
--
Mick Doherty

http://www.dotnetrix.co.uk/nothing.html

>
>
"Nick" <a@a.comwrote in message
news:#ju3Sp79IH A.3884@TK2MSFTN GP05.phx.gbl...

>Hi there,
>>
>I'm trying to create a random number via a seed in VB.NET and C++, 2
>different applications. I want to be able to use the same seed and get
>the same random number but unfortunately VB.NET's Random class produces a
>different set of results than the C++ rnd function.
>>
>I can't see any reference of rnd being used via API declarations and am
>just trying to find a way of generating a random number via seed that is
>identical in both languages. Of course I could create a C++ DLL to do it
>for me and use it in the VB app, but i'd rather not go to that extreme
>for 1 method.
>>
>Any suggestions would be greatly appreciated!
>>
>Nick.
>>

>

[Nick]

Re: VB.NET Random / C++ rnd

right, I've cracked and I now have a managed C++ class library which exposes
the C runtime methods.

"Mick Doherty"
<EXCHANGE#WITH@ AND.REMOVE.SQUA REBRACKETS.[mdaudi100#ntlwo rld.com]wrote in
message news:u1BuNq89IH A.1192@TK2MSFTN GP05.phx.gbl...

Does 'Microsoft.Visu alBasic.VBMath. Rnd' produce the same results as your
C++ rnd() method?
>
--
Mick Doherty

http://www.dotnetrix.co.uk/nothing.html

>
>
"Nick" <a@a.comwrote in message
news:#ju3Sp79IH A.3884@TK2MSFTN GP05.phx.gbl...

>Hi there,
>>
>I'm trying to create a random number via a seed in VB.NET and C++, 2
>different applications. I want to be able to use the same seed and get
>the same random number but unfortunately VB.NET's Random class produces a
>different set of results than the C++ rnd function.
>>
>I can't see any reference of rnd being used via API declarations and am
>just trying to find a way of generating a random number via seed that is
>identical in both languages. Of course I could create a C++ DLL to do it
>for me and use it in the VB app, but i'd rather not go to that extreme
>for 1 method.
>>
>Any suggestions would be greatly appreciated!
>>
>Nick.
>>

>

[Feng Chen[MSFT]]

Re: VB.NET Random / C++ rnd

Hello Nick,

Yes, use managed C++ can wrap the native functions in a library and use it
in .net applications. In addition, we can also import and directly call the
C runtime functions in the VB.net application using P/Invoke:

<DllImport
("msvcr80.dll", EntryPoint:="ra nd",CallingConv ention:=Calling Convention.Cdec l
)>
Public Shared Function rand() As Integer
End Function
<DllImport("msv cr80.dll", EntryPoint:="sr and", CallingConventi on:=
CallingConventi on.Cdecl)>
Public Shared Sub srand(ByVal _Seed As UInteger)
End Sub

Please let me know if you have any other concerns, or need anything else.

Best regards,
Feng Chen
Microsoft Online Community Support

Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
msdnmg@microsof t.com.
=============== =============== =============== =====
Get notification to my posts through email? Please refer to

http://msdn.microsoft.com/subscriptions/managednewsgroups/default.aspx#notif

ications .

Note: The MSDN Managed Newsgroup support offering is for non-urgent issues
where an initial response from the community or a Microsoft Support
Engineer within 1 business day is acceptable. Please note that each follow
up response may take approximately 2 business days as the support
professional working with you may need further investigation to reach the
most efficient resolution. The offering is not appropriate for situations
that require urgent, real-time or phone-based interactions or complex
project analysis and dump analysis issues. Issues of this nature are best
handled working with a dedicated Microsoft Support Engineer by contacting
Microsoft Customer Support Services (CSS) at
http://msdn.microsoft.com/subscripti...t/default.aspx .
=============== =============== =============== =====
This posting is provided "AS IS" with no warranties, and confers no rights.

[Feng Chen[MSFT]]

Re: VB.NET Random / C++ rnd

Hello Nick,

Yes, use managed C++ can wrap the native functions in a library and use it
in .net applications. In addition, we can also import and directly call the
C runtime functions in the VB.net application using P/Invoke:

<DllImport
("msvcr80.dll", EntryPoint:="ra nd",CallingConv ention:=Calling Convention.Cdec l
)>
Public Shared Function rand() As Integer
End Function
<DllImport("msv cr80.dll", EntryPoint:="sr and", CallingConventi on:=
CallingConventi on.Cdecl)>
Public Shared Sub srand(ByVal _Seed As UInteger)
End Sub

Please let me know if you have any other concerns, or need anything else.

Best regards,
Feng Chen
Microsoft Online Community Support

Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
msdnmg@microsof t.com.
=============== =============== =============== =====
Get notification to my posts through email? Please refer to

http://msdn.microsoft.com/subscriptions/managednewsgroups/default.aspx#notif

ications .

Note: The MSDN Managed Newsgroup support offering is for non-urgent issues
where an initial response from the community or a Microsoft Support
Engineer within 1 business day is acceptable. Please note that each follow
up response may take approximately 2 business days as the support
professional working with you may need further investigation to reach the
most efficient resolution. The offering is not appropriate for situations
that require urgent, real-time or phone-based interactions or complex
project analysis and dump analysis issues. Issues of this nature are best
handled working with a dedicated Microsoft Support Engineer by contacting
Microsoft Customer Support Services (CSS) at
http://msdn.microsoft.com/subscripti...t/default.aspx .
=============== =============== =============== =====
This posting is provided "AS IS" with no warranties, and confers no rights.

[=?ISO-8859-1?Q?G=F6ran_Andersson?=]

Re: VB.NET Random / C++ rnd

Nick wrote:

Hi there,
>
I'm trying to create a random number via a seed in VB.NET and C++, 2
different applications. I want to be able to use the same seed and get the
same random number but unfortunately VB.NET's Random class produces a
different set of results than the C++ rnd function.
>
I can't see any reference of rnd being used via API declarations and am just
trying to find a way of generating a random number via seed that is
identical in both languages. Of course I could create a C++ DLL to do it
for me and use it in the VB app, but i'd rather not go to that extreme for 1
method.
>
Any suggestions would be greatly appreciated!
>
Nick.
>
>

You can easily roll your own random method that is reproducable in most
any language. Here is one in C# (excuse me for posting in vb) for
creating a byte random number:


private byte _seed = 1;

public byte Rnd() {
_seed = byte((int)_seed * 251 + 1);
return _seed;
}


The algorithm is simple: multiply the seed with a large enough prime
number, add one, and throw away any overflow bits.

For data types larger than a byte you would use a larger prime number,
something close to it's max value.

I picked up this algorithm many years ago from the random function in
Turbo Pascal. There are more advanced algorithms that gives a bit better
randomness, but I thought that you would want simplicity rather than
extreme randomness.

--
Göran Andersson
_____

http://www.guffa.com

[Feng Chen[MSFT]]

Re: VB.NET Random / C++ rnd

Hello Nick,

I haven't seen your reply after I last posted my reply, I'm writing to
check the status of this post. Please feel free to let me know if there's
anything else I can help.

Best regards,
Feng Chen
Microsoft Online Community Support
=============== =============== ===========
Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
msdnmg@microsof t.com.

This posting is provided "AS IS" with no warranties, and confers no rights.

[Nick]

Re: VB.NET Random / C++ rnd

Hi Fenh,

Tis okay I said that I had sorted the problem, although I'm not using
the method via DLL Imports, I've wrapped the methods so that they are more
like the native .NET Random class but produce the same results as the C
Runtime calls.

Nick.

""Feng Chen[MSFT]"" <v-fengch@online.m icrosoft.comwro te in message
news:z9mwlUT%23 IHA.5076@TK2MSF TNGHUB02.phx.gb l...

Hello Nick,
>
I haven't seen your reply after I last posted my reply, I'm writing to
check the status of this post. Please feel free to let me know if there's
anything else I can help.
>
Best regards,
Feng Chen
Microsoft Online Community Support
=============== =============== ===========
Delighting our customers is our #1 priority. We welcome your comments and
suggestions about how we can improve the support we provide to you. Please
feel free to let my manager know what you think of the level of service
provided. You can send feedback directly to my manager at:
msdnmg@microsof t.com.
>
This posting is provided "AS IS" with no warranties, and confers no
rights.
>