C / C++ / MFC

Re: random (or pseudo) random array of 100.000 positions

21-Oct-04 5:13

Hi guys
Somebody knows what's the fast way to generate a random (or pseudorandom) array of numbers of 100.000 positions?
Thanks in advance
Doc

David Crow21-Oct-04 5:27

Re: random (or pseudo) random array of 100.000 positions

21-Oct-04 5:27

Are you wanting 100,000 numbers, or are you wanting numbers with 100,000 digits?

"Opinions are neither right nor wrong. I cannot change your opinion of me. I can, however, change what influences your opinion." - David Crow

doctorpi21-Oct-04 5:30

Re: random (or pseudo) random array of 100.000 positions

21-Oct-04 5:30

I want a list of 100.000 numbers randomly sorted.

Doc

David Crow21-Oct-04 5:46

Re: random (or pseudo) random array of 100.000 positions

21-Oct-04 5:46

doctorpi wrote:
I want a list...

But the subject indicates an array. I'll show an example for an array.

int nNumbers[100000];
// might want to call srand() here
for (int x = 0; x < sizeof(nNumbers) / sizeof(int); x++)
    nNumbers[x] = rand();

"Opinions are neither right nor wrong. I cannot change your opinion of me. I can, however, change what influences your opinion." - David Crow

doctorpi21-Oct-04 5:52

Re: random (or pseudo) random array of 100.000 positions

21-Oct-04 5:52

Thanks
But maybe I haven't explained me well.
At the beginning I have an array where nNumbers[i]=i; then I have 100.000 numbers. After the process that I don't know how to do I want to have the array with all the numbers from 0 to 100.000 but unsorted.
I'm thinking in exchange 2 positions N times, but how I can generate a number between 0 and 100.000 because rand() is not valid for me.
Thanks again
Doc

David Crow21-Oct-04 6:09

Re: random (or pseudo) random array of 100.000 positions

21-Oct-04 6:09

doctorpi wrote:
...how I can generate a number between 0 and 100.000 because rand() is not valid for me.

You are right. rand() returns a maximum value of RAND_MAX. Here is a pseudo-random number generator that I've used in the past:

static unsigned long Seed = 1;
 
#define A 48271L
#define M 2147483647L
#define Q (M/A)
#define R (M%A)
 
double Random( void )
{
    long TmpSeed;
 
    TmpSeed = A * (Seed % Q) - R * (Seed / Q);
    if (TmpSeed >= 0)
        Seed = TmpSeed;
    else
        Seed = TmpSeed + M;
 
    return (double) Seed / M;
}
 
void Init( unsigned long InitVal )
{
    Seed = InitVal;
}

"Opinions are neither right nor wrong. I cannot change your opinion of me. I can, however, change what influences your opinion." - David Crow

PJ Arends21-Oct-04 6:24

PJ Arends

21-Oct-04 6:24

http://www.codeproject.com/cpp/mersennetwisterclass.asp[^]

Use the RandomRange function.

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"Obviously ??? You're definitely a superstar!!!" mYkel - 21 Jun '04

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Re: random (or pseudo) random array of 100.000 positions

doctorpi21-Oct-04 6:26

Internet suggestion needed

21-Oct-04 6:26

Thanks guys
I think I've got it.

Doc

includeh1021-Oct-04 4:21

includeh10

21-Oct-04 4:21

Hi all,
We hope customers get new info from our web on time.

I want to do in this way:
add a web-page which includes some texts, i.e. "expire", "update" etc.
when program (used by customers) is running, it reads the web-page (it is hidden from customers) and does something according to texts on the page.

I don't want to use tcp/ip - we only have simply tasks.
do you know how to download a web-page silently (users don't know)?
or any other suggestions for my needed?

thx

includeh10

Re: Internet suggestion needed

Yulianto.21-Oct-04 22:47

Yulianto.

21-Oct-04 22:47

Why do you want the user to use an application which read a web page, why not use only the web page, with no application. Maybe you should use the CHTMLView, or something like that, I forgot the class

<italic>Work hard and a bit of luck is the key to success.

You don`t need to be genius, to be rich.

Re: Internet suggestion needed

Yulianto.21-Oct-04 22:51

Yulianto.

21-Oct-04 22:51

I know try using CWebBrowser

<italic>Work hard and a bit of luck is the key to success.

You don`t need to be genius, to be rich.

PostMessage Help

Keith La Force21-Oct-04 4:03

Keith La Force

21-Oct-04 4:03

Hi, I am trying to use the PostMessage function by importing it through DLL import in C# with the following definition.

[DllImport("user32.dll")]
static extern bool PostMessage(IntPtr hWnd, int msg, Int32 wParam, IntPtr lParam);

Can someone give an example of what you would pass in order to get a keystroke, and a mouse click? Really, I do not understand what needs to go in for wParam, or lParam.

Thank you for your help in advance.

Re: PostMessage Help

Phil J Pearson21-Oct-04 4:10

Phil J Pearson

21-Oct-04 4:10

It depends what you need at the other end; there's a simple answer and a complicated one.

The simple answer is to look in MSDN for:
Keystroke: WM_CHAR
Mouse click: WM_xBUTTONy (where x is L or R and y is UP, DOWN or DBLCLK)

It can be more complicated if you need WM_KEYDOWN, WM_KEYUP, WM_SYSKEYDOWN, WM_SYSKEYUP, WM_SYSCHAR and so on.

The opinions expressed in this communication do not necessarily represent those of the author (especially if you find them impolite, discourteous or inflammatory).

sizeof(), can u explain?

includeh1021-Oct-04 3:39

includeh10

21-Oct-04 3:39

struct S2
{
WORD w0;
};

struct S6A
{
WORD w0;
DWORD dw0;
};
struct S6B
{
WORD w0,w1;
WORD w2;
};

struct S10A
{
WORD w0;
DWORD dw0;
DWORD dw1;
};
struct S10B
{
WORD w0,w1,w2,w3,w4;
};

if use sizeof() to calculate size of structs above, they are
2, 8, 6, 12, 10 respectively (tested on windows OS - not DOS).

align? why in this way?

includeh10

Michael Dunn21-Oct-04 3:45

Michael Dunn

21-Oct-04 3:45

Structs/classes are padded internally to make members aligned properly (most common CPUs other than x86 will fault on unaligned memory access). So in the case of:

struct S6A
{
  WORD w0;
  DWORD dw0;
};

if dw0 came right after w0 in memory, it would not lie on a DWORD boundary, so 2 bytes of padding are added to make dw0 aligned. This behavior can be changed with #pragma pack.

--
I'm Michael Dunn and I approve this post.

Vote Trogdor in oh-four!

David Crow21-Oct-04 3:46

21-Oct-04 3:46

By default structs are aligned on 8-byte boundaries. If you are having alignment problems, check out the #pramga pack directive, or the /Zp compiler switch.

"Opinions are neither right nor wrong. I cannot change your opinion of me. I can, however, change what influences your opinion." - David Crow

Anonymous21-Oct-04 3:48

Anonymous

21-Oct-04 3:48

DWORDS can only appear at offsets which are a multiple of four. (sizeof(DWORD))

Compilers are required to lay out a structures members in the same order as they are declared.

Put these two together... the compiler must insert padding.

includeh1021-Oct-04 3:51

includeh10

21-Oct-04 3:51

struct S2
{
WORD w0;
};

why sizeof(S2) is 2, not 4?

includeh10