Generating random numbers

nkhambal · #1 25-Apr-2005, 17:39

Hi all,

I need to generate and store 2 arrays of 255 unique random integers each. i.e.

CPP / C++ / C Code:

unsigned short int arr1[255];

unsigned short int arr2[255];

Both the arrays should have unique numbers and they should be in the range 1-65535.

Can someone suggest some solution to this problem?

Thanks,

cable_guy_67 · #2 25-Apr-2005, 18:23

The GenSeq() might be just what you are looking for. It generates a unique array for a deck of cards. You can find it in this thread.

Hope it helps.

Mark

nkhambal · #3 25-Apr-2005, 18:23

Okey,After googling for sometime, and collecting some bits and pieces of info I wrote this program. It generates 2 arrays of size 255 each with unique integer in the range 1 to 65535.

Anybody want to regress it ?

CPP / C++ / C Code:

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

#define MAX_NO 65535
#define RANDSIZE 65535

int count=255;

void initrandom(unsigned seed){
 
  static char randstate[RANDSIZE];
  initstate(seed, randstate, RANDSIZE);
}

void compare_arr(unsigned short int arr1[],unsigned short int arr2[])
{
	int i,j;
	int dup=0;
	int dupcount=0;
	for (i=0;i<count;i++)
	  {
		for (j=0;j<i;j++)
		{
		  if (arr1[i] == arr2 [j])
		  {
			dup = 1; 
			dupcount++;
			printf("arr1[%d] = %d\n",i,arr1[i]);
			printf("arr2[%d] = %d\n",j,arr2[j]);
			
		  } else {
			if (!dup) /* set dup to 0 only if its not already set to 1 */
			{
			  dup = 0;
			}
		  }
		}
	  }

  if (dup)
  {
    printf("\n%d Duplicate found\n",dupcount);
  } else {
    printf("\nNo Duplicate found\n");
  }
}

int main(int argc, char *argv[])
{
	unsigned short int arr1[255];
	unsigned short int arr2[255];
	
	int i,j;
	int dup = 0 ;
	int dupcount=0;
	
	printf("%ld\n",RAND_MAX);

	initrandom(time(NULL));
		
	for (j=0;j<count;j++)
	{
		arr1[j]= random();
	}
	
	for (j=0;j<count;j++)
	{
		arr2[j]= random();
	}
	printf("\ns/n\tarr1\tarr2\n\n");
	for (j=0;j<count;j++)
	{
		printf("%d\t%d\t%d\n",j,arr1[j],arr2[j]);
	}
	
	compare_arr(arr1,arr2);
	
	return 0;
}

Thanks,

nkhambal · #4 25-Apr-2005, 19:46

okey, here is another version. A little customized to my requirement. I have now 3 arrays, each of size 255 and with unique integer. My earlier code in previous post used to generate duplicates with multiple runs. This one takes care of that.

Not very elegent one, but working solution.

CPP / C++ / C Code:

#include <stdio.h>

typedef uint8_t CARD8;
typedef uint16_t CARD16;
typedef uint32_t CARD32;

#define RANDSIZE 65535

typedef enum 
{
	FALSE,
	TRUE
}boolean;

void initrandom(unsigned seed){
 
  static char randstate[RANDSIZE];
  initstate(seed, randstate, RANDSIZE);
}

void rand_gen16(CARD16 arr[],int size)
{
	int j;
	static int first_time = TRUE;

	if (first_time)
	{
		initrandom(time(NULL));
		first_time=FALSE;
	}
	
	for (j=0;j<size;j++)
	{
		arr[j]= random();
	}
}

boolean compare_arr(CARD16 arr1[],CARD16 arr2[],int count)
{
	int i,j;
	int dup=0;
	
	for (i=0;i<count;i++)
	{
		for (j=0;j<i;j++)
		{
		  if (arr1[i] == arr2 [j])
		  {
			dup = 1; 
		  } else {
			if (!dup) /* set dup to 0 only if its not already set to 1 */
			{
			  dup = 0;
			}
		  }
		}
	}

  if (dup)
  {
    return FALSE;
  } else {
    return TRUE;
  }
}

void compare_arr1(CARD16 arr1[],CARD16 arr2[],int count)
{
	int i,j;
	int dup=0;
	int dupcount=0;
	for (i=0;i<count;i++)
	{
		for (j=0;j<i;j++)
		{
		  if (arr1[i] == arr2 [j])
		  {
			dup = 1; 
			dupcount++;
			printf("arr1[%d] = %d\n",i,arr1[i]);
			printf("arr2[%d] = %d\n",j,arr2[j]);
			
		  } else {
			if (!dup) /* set dup to 0 only if its not already set to 1 */
			{
			  dup = 0;
			}
		  }
		}
	}

  if (dup)
  {
    printf("\n%d Duplicate found\n",dupcount);
  } else {
    printf("\nNo Duplicate found\n");
  }
}

void myrandom(CARD16 arr1[],CARD16 arr2[],CARD16 arr3[],int size)
{
	boolean result= FALSE;
	do
	{
		rand_gen16(arr1,size);
		rand_gen16(arr2,size);
		rand_gen16(arr3,size);

		if ((result=compare_arr(arr1,arr1,size)) == FALSE )
		{
			goto END;
		} else if ((result=compare_arr(arr2,arr2,size)) == FALSE)
		{
			goto END;
		} else if ((result=compare_arr(arr3,arr3,size)) == FALSE)
		{
			goto END;
		} else if ((result=compare_arr(arr1,arr2,size)) == FALSE)
		{
			goto END;
		} else if ((result=compare_arr(arr1,arr3,size)) == FALSE)
		{
			goto END;
		} else if ((result=compare_arr(arr2,arr3,size)) == FALSE)
		{
			goto END;
		}
		END:
	} while (result==FALSE);
}

int main(int argc, char *argv[])
{
	unsigned short int arr1[255];
	unsigned short int arr2[255];
	unsigned short int arr3[255];
	int size=255;
	
	myrandom(arr1,arr2,arr3,size);

	printf("Self Compare\n");
	compare_arr1(arr1,arr1,size);
	compare_arr1(arr2,arr2,size);
	compare_arr1(arr3,arr3,size);
	printf("\nCompare with others\n");
	compare_arr1(arr1,arr2,size);
	compare_arr1(arr1,arr3,size);
	compare_arr1(arr2,arr3,size);
	
	return 0;
}

cable_guy_67 · #5 26-Apr-2005, 00:25

I think this is about the same thing. If I find a "0" I know I have not found a match. I don't really know the proper way to pass the multidim arrays but this seems to work.

CPP / C++ / C Code:

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

#define MAXRAND 65535
const int ARRSIZE = 255;
const int ARRNUM  = 3;

void RndInit(){
  static int doorslam = 1;
  static char randstate[MAXRAND];

  if (doorslam){
    initstate(time(NULL), randstate, MAXRAND);
    doorslam = 0;
  }
}

int IsUnique(unsigned int* array[ARRNUM][ARRSIZE], int value){
  int i, j;

  for ( i=0; i<ARRNUM; i++){
    for ( j=0; j<ARRSIZE; j++){
      if (array[i][j] == 0){
        /* We made through all the placed numbers */
        /* without finding a match                */
/*        printf("Unique\n"); */
        return 1;
      }
      else if (array[i][j] == value){
        /* This is a duplicate 'drat!' */
/*        printf("Not Unique\t"); */
        return 0;
      }
    }
  }
  return 0;
}

void GenUnique(unsigned int* array[ARRNUM][ARRSIZE]){
  int searching;
  int newnumber;
  int i, j;

  for ( i=0; i<ARRNUM; i++){
    for ( j=0; j<ARRSIZE; j++){
      /* get a random number and place in array */
      searching = 1;
      do{
        newnumber = (random()%MAXRAND) + 1;
        if (IsUnique(array,newnumber)){
          array[i][j] = newnumber;
          searching = 0;
/*          printf("array[%d][%d] = %d\t", i,j,array[i][j]); */
        }
      }while (searching);
    }
  }
}

void PrintArray(unsigned int* array[ARRNUM][ARRSIZE]){
  int i, j;
  for ( i=0; i<ARRNUM; i++){
    for ( j=0; j<ARRSIZE; j++){
      printf("array[%d][%d] = %d\n", i,j,array[i][j]);
    }
  }
}

int main(){
printf("Random Numbers\n");
  unsigned int array[ARRNUM][ARRSIZE];
  RndInit();
  GenUnique(array);
  PrintArray(array);
  return 0;
}

cable_guy_67 · #6 26-Apr-2005, 07:49

A few changes to shut up my compiler and some printing additions.

CPP / C++ / C Code:

void GenUnique(unsigned int array[ARRNUM][ARRSIZE]){
  int searching;
  int newnumber;
  int i, j;

  /* Zero the array for multiple runs */
  for (i=0; i<ARRNUM; i++)
    for (j=0; j<ARRSIZE; j++)
      array[i][j] = 0;


void PrintArray(unsigned int array[ARRNUM][ARRSIZE]){
  int i, j;
  for ( i=0; i<ARRNUM; i++){
    for ( j=0; j<ARRSIZE; j++){
      printf("array[%d][%d] = %d\n", i,j,array[i][j]);
    }
  }
}

void PrintArrayNum(unsigned int array[ARRNUM][ARRSIZE],int value){
  int i;
  for ( i=0; i<ARRSIZE; i++){
    printf("array[%d][%d] = %d\n", value,i,array[value][i]);
  }
}


int main(){
//  printf("Random Numbers\n");
  unsigned int array[ARRNUM][ARRSIZE];
  RndInit();
  GenUnique(array);
//  PrintArray(array);
  PrintArrayNum(array,1);
  GenUnique(array);
  PrintArrayNum(array,1);
  return 0;
}

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