```/* nag_prob_poisson_vector (g01skc) Example Program.
*
* Copyright 2017 Numerical Algorithms Group.
*
* Mark 26.1, 2017.
*/
#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagg01.h>

int main(void)
{
/* Integer scalar and array declarations */
Integer lk, ll, i, lout;
Integer *ivalid = 0, *k = 0;
Integer exit_status = 0;

/* NAG structures */
NagError fail;

/* Double scalar and array declarations */
double *peqk = 0, *pgtk = 0, *plek = 0, *l = 0;

/* Initialize the error structure to print out any error messages */
INIT_FAIL(fail);

printf("nag_prob_poisson_vector (g01skc) Example Program Results\n\n");

/* Skip heading in data file */
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%*[^\n] ", &ll);
if (!(l = NAG_ALLOC(ll, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
for (i = 0; i < ll; i++)
scanf("%lf", &l[i]);
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%*[^\n] ", &lk);
if (!(k = NAG_ALLOC(lk, Integer)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
for (i = 0; i < lk; i++)
scanf("%" NAG_IFMT "", &k[i]);
scanf("%*[^\n] ");

/* Allocate memory for output */
lout = MAX(ll, lk);
if (!(peqk = NAG_ALLOC(lout, double)) ||
!(pgtk = NAG_ALLOC(lout, double)) ||
!(plek = NAG_ALLOC(lout, double)) ||
!(ivalid = NAG_ALLOC(lout, Integer)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Calculate probability */
nag_prob_poisson_vector(ll, l, lk, k, plek, pgtk, peqk, ivalid, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_prob_poisson_vector (g01skc).\n%s\n",
fail.message);
exit_status = 1;
if (fail.code != NW_IVALID)
goto END;
}

/* Display title */
printf("     l         k       plek      pgtk      peqk  ivalid\n");
printf(" --------------------------------------------------------\n");

/* Display results */
for (i = 0; i < lout; i++)
printf(" %6.2f    %6" NAG_IFMT "    %6.3f    %6.3f    %6.3f   %3" NAG_IFMT
"\n", l[i % ll], k[i % lk], plek[i], pgtk[i], peqk[i], ivalid[i]);

END:
NAG_FREE(l);
NAG_FREE(k);
NAG_FREE(plek);
NAG_FREE(pgtk);
NAG_FREE(peqk);
NAG_FREE(ivalid);

return (exit_status);
}
```