```/* nag_rand_poisson (g05tjc) Example Program.
*
* Copyright 2014 Numerical Algorithms Group.
*
* Mark 9, 2009.
*/
/* Pre-processor includes */
#include <stdio.h>
#include <math.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagg05.h>

int main(void)
{
/* Integer scalar and array declarations */
Integer     exit_status = 0;
Integer     lr, i, lstate;
Integer     *state = 0, *x = 0;

/* NAG structures */
NagError    fail;
Nag_ModeRNG mode;

/* Double scalar and array declarations */
double      *r = 0;

/* Set the distribution parameters */
double      lambda = 20.0e0;

/* Set the sample size */
Integer     n = 10;

/* Choose the base generator */
Nag_BaseRNG genid = Nag_Basic;
Integer     subid = 0;

/* Set the seed */
Integer     seed[] = { 1762543 };
Integer     lseed = 1;

/* Initialise the error structure */
INIT_FAIL(fail);

printf("nag_rand_poisson (g05tjc) Example Program Results\n\n");

/* Get the length of the state array */
lstate = -1;
nag_rand_init_repeatable(genid, subid, seed, lseed, state, &lstate, &fail);
if (fail.code != NE_NOERROR)
{
printf("Error from nag_rand_init_repeatable (g05kfc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Calculate the size of the reference vector */
lr = 30 + 20 * sqrt(lambda) + lambda;

/* Allocate arrays */
if (!(r = NAG_ALLOC(lr, double)) ||
!(state = NAG_ALLOC(lstate, Integer)) ||
!(x = NAG_ALLOC(n, Integer)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Initialise the generator to a repeatable sequence */
nag_rand_init_repeatable(genid, subid, seed, lseed, state, &lstate, &fail);
if (fail.code != NE_NOERROR)
{
printf("Error from nag_rand_init_repeatable (g05kfc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Generate the variates, initialising the reference vector
at the same time */
mode = Nag_InitializeAndGenerate;
nag_rand_poisson(mode, n, lambda, r, lr, state, x, &fail);
if (fail.code != NE_NOERROR)
{
printf("Error from nag_rand_poisson (g05tjc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Display the variates*/
for (i = 0; i < n; i++)
printf("%ld\n", x[i]);

END:
NAG_FREE(r);
NAG_FREE(state);
NAG_FREE(x);

return exit_status;
}
```