```/* nag_approx_quantiles_fixed (g01anc) Example Program.
*
* Copyright 2017 Numerical Algorithms Group.
*
* Mark 26.2, 2017.
*/

#include <nag.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nagg01.h>

int main(void)
{
/* Scalars */
Integer exit_status = 0;
Integer i, ind, j, licomm, lrcomm, n, nb, np, nq, nrv;
double eps;
/* Arrays */
double *q = 0, *qv = 0, *rcomm = 0, *rv = 0, trcomm, trv;
Integer *icomm = 0, ticomm;
/* Nag Types */
NagError fail;

INIT_FAIL(fail);

printf("nag_approx_quantiles_fixed (g01anc) Example Program Results\n");

/* Skip heading in data file */
scanf("%*[^\n]");

/* Read in the problem size */
scanf("%" NAG_IFMT "%*[^\n] ", &n);
scanf("%lf%*[^\n] ", &eps);
scanf("%" NAG_IFMT "%*[^\n] ", &nq);

if (!(qv = NAG_ALLOC(nq, double)) || !(q = NAG_ALLOC(nq, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Read in the quantiles that are required */
for (i = 0; i < nq; ++i)
scanf("%lf", &q[i]);
scanf("%*[^\n] ");

/* Call the routine for the first time to obtain lrcomm and licomm */
nb = lrcomm = 1;
licomm = 2;
ind = 0;
nag_approx_quantiles_fixed(&ind, n, trv, nb, eps, &np, q, qv,
nq, trcomm, lrcomm, ticomm, licomm, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_approx_quantiles_fixed (g01anc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Use calculated array sizes to allocate the communication arrays */
lrcomm = ticomm;
licomm = ticomm;
if (!(rcomm = NAG_ALLOC(lrcomm, double)) ||
!(icomm = NAG_ALLOC(licomm, Integer)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Read in the number of blocks of data */
scanf("%" NAG_IFMT "%*[^\n] ", &nrv);

/* Loop over each block of data */
for (i = 0; i < nrv; ++i) {

/* Read in the size of the i'th block of data */
scanf("%" NAG_IFMT "%*[^\n] ", &nb);

/* Reallocate rv */
NAG_FREE(rv);
if (!(rv = NAG_ALLOC(nb, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Read in the data for the i'th block */
for (j = 0; j < nb; ++j)
scanf("%lf", &rv[j]);
scanf("%*[^\n] ");

/* Update the summaries based on the i'th block of data */
nag_approx_quantiles_fixed(&ind, n, rv, nb, eps, &np, q, qv, nq,
rcomm, lrcomm, icomm, licomm, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_approx_quantiles_fixed (g01anc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}
if (ind == 4)
break;
}

/* Call the routine again to calculate quantiles specified in vector q */
ind = 3;
nag_approx_quantiles_fixed(&ind, n, rv, nb, eps, &np, q, qv, nq, rcomm,
lrcomm, icomm, licomm, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_approx_quantiles_fixed (g01anc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

/* Print the results */
printf("\n    Input data:\n");
printf("    %" NAG_IFMT " observations\n", n);
printf("    eps = %5.2f\n", eps);
printf("    Quantile   Result\n\n");
for (i = 0; i < nq; ++i) {
printf("  %7.2f    %7.2f\n", q[i], qv[i]);
}

END:
NAG_FREE(rv);
NAG_FREE(q);
NAG_FREE(qv);
NAG_FREE(rcomm);
NAG_FREE(icomm);

return exit_status;
}
```