Announcement

**Thomas Albinus** · 26.06.2003, 07:47

Hallo!

Anbei ein kleines Beispielprogramm. Damit bekommst Du Pseudozufallszahlen im Bereich von 0 bis RAND_MAX. F�r einen anderen Bereich ist eine kleine Umrechnung n�tig:

<PRE>
Min+((double) rand())/RAND_MAX*(Max-Min)
</PRE>

Damit liegen die Zahlen dann im Bereich von Min bis Max.

Ich hoffe ich konnte helfen?

Viele Gr��e 
Thomas

<PRE>
/* RAND.C: This program seeds the random-number generator
* with the time, then displays 10 random integers.
*/

#include <stdlib.h>
#include <stdio.h>
#include <time.h>

void main( void )
{
int i;

/* Seed the random-number generator with current time so that
* the numbers will be different every time we run.
*/
srand( (unsigned)time( NULL ) );

/* Display 10 numbers. */
for( i = 0; i < 10;i++ )
printf( " %6d\n", rand() );
}

</PRE&gt

**Geoffrey** · 04.07.2003, 09:19

Hi 
Folgendes habe ich mir selbst zusammengestrickt. Basis ist der von mir unten empfohlene RANMAR Zufallsgenerator.
Sieht kompliziert und ungl�cklich Programmiert aus - ist aber ein WIRKLICH FANTASTISCHER Zufalls-Generator!!!! 

//In stdafx.h 
#include <afxtempl.h> 

//In DEINE ???.h 
BOOL bTest; 
int i97, j97; 
float u[98], c, cd, cm; 
float ranmar(); 
void rmarin(int ij, int kl); 
int Rnd(int intMax, BOOL NegFlag); 
 
//In DEINE ????.cpp 

int C????Wnd::Rnd(int intMax, BOOL NegativFlag) 
{ 
double xZahl = ranmar(); 
if(NegativFlag) 
return ((double)xZahl - (int)xZahl) * intMax; 
else 
return abs((((double)xZahl - (int)xZahl) * intMax)); 
} 

void C????Wnd::rmarin(int ij, int kl) 
{ 
/*
C This is the initialization routine for the random number generator RANMAR()
C NOTE: The seed variables can have values between: 0 <= IJ <= 31328
C 0 <= KL <= 30081
C The random number sequences created by these two seeds are of sufficient
C length to complete an entire calculation with. For example, if sveral
C different groups are working on different parts of the same calculation,
C each group could be assigned its own IJ seed. This would leave each group
C with 30000 choices for the second seed. That is to say, this random
C number generator can create 900 million different subsequences -- with
C each subsequence having a length of approximately 10^30.
C
C Use IJ = 1802 & KL = 9373 to test the random number generator. The
C subroutine RANMAR should be used to generate 20000 random numbers.
C Then display the next six random numbers generated multiplied by 4096*4096
C If the random number generator is working properly, the random numbers
C should be:
C 6533892.0 14220222.0 7275067.0
C 6172232.0 8354498.0 10633180.0
*/ 
int i, j, k, l, ii, jj, m; 
float s, t; 

ij %= 31328; 
kl %= 30081; 

i = (ij/177)%177 + 2; 
j = ij%177 + 2; 
k = (kl/169)%178 + 1; 
l = kl%169; 

for (ii=1; ii<=97; ii++) { 
s = (float)0.0; 
t = (float)0.5; 
for (jj=1; jj<=24; jj++) { 
m = (((i*j)%179)*k) % 179; 
i = j; 
j = k; 
k = m; 
l = (53*l + 1) % 169; 
if ((l*m)%64 >= 32) s += t; 
t *= (float)0.5; 
 }
u[ii] = s; 
} 

c = (float)362436.0 / (float)16777216.0; 
cd = (float)7654321.0 / (float)16777216.0; 
cm = (float)16777213.0 / (float)16777216.0; 

i97 = 97; 
j97 = 33; 

bTest = TRUE; 
 } 

float C????Wnd::ranmar() 
{ 
float uni; 

// auto-seed: 
if (bTest==FALSE) 
{ 
rmarin(rand() % 31328, time( NULL ) % 30081); 
} 

uni = u[i97] - u[j97]; 
if (uni < 0.0) uni += (float)1.0; 
u[i97] = uni; 
i97--; 
if (i97==0) i97 = 97; 
j97--; 
if (j97==0) j97 = 97; 
c -= cd; 
if (c<0.0) c += cm; 
uni -= c; 
if (uni<0.0) uni += (float)1.0; 
return uni; 
} 

Aufruf: 
BOOL NFlag = FALSE; //TRUE = Zuf.Negative Zahlen 
int max = 1000; 
int Zufall = Rnd(max, NFlag);<BR&gt

Announcement

FRESH MEAT sucht HILFE in RANDOMIZE

FRESH MEAT sucht HILFE in RANDOMIZE

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