```/* nag_2d_panel_sort (e02zac) Example Program.
*
* Copyright 2017 Numerical Algorithms Group.
*
* Mark 26.2, 2017.
*/

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nage02.h>

int main(void)
{
/* Scalars */

/* Arrays */
double *lamda = 0, *mu = 0, *x = 0, *y = 0;
Integer *point = 0;

/* Nag types */
NagError fail;

exit_status = 0;
INIT_FAIL(fail);

printf("nag_2d_panel_sort (e02zac) Example Program Results\n");

/* Skip heading in data file */
scanf("%*[^\n] ");
while (scanf("%" NAG_IFMT "%*[^\n] ", &m) != EOF)
{
if (m > 0) {
/* Allocate memory */
if (!(x = NAG_ALLOC(m, double)) || !(y = NAG_ALLOC(m, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
}
else {
printf("Invalid m.\n");
exit_status = 1;
return exit_status;
}
scanf("%" NAG_IFMT "%" NAG_IFMT "%*[^\n] ", &px, &py);
nadres = (px - 7) * (py - 7);
if (px >= 8 && py >= 8) {
/* Allocate memory */
if (!(lamda = NAG_ALLOC(px, double)) ||
!(mu = NAG_ALLOC(py, double)) ||
!(point = NAG_ALLOC(npoint, Integer)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
}
else {
printf("Invalid px or py.\n");
exit_status = 1;
goto END;
}

/* Read data points and intercepts of panel sides */
for (i = 1; i <= m; ++i) {
scanf("%lf%lf", &x[i - 1], &y[i - 1]);
}
scanf("%*[^\n] ");

if (px > 8) {
for (i = 5; i <= px - 4; ++i) {
scanf("%lf", &lamda[i - 1]);
}
scanf("%*[^\n] ");
}
if (py > 8) {
for (i = 5; i <= py - 4; ++i) {
scanf("%lf", &mu[i - 1]);
}
scanf("%*[^\n] ");
}
/* Sort points into panel order */

/* nag_2d_panel_sort (e02zac).
* Sort two-dimensional data into panels for fitting bicubic
* splines
*/
nag_2d_panel_sort(px, py, lamda, mu, m, x, y, point, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_2d_panel_sort (e02zac).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

/* Output points in panel order */
for (i = 1; i <= nadres; ++i) {
printf("\n%s%4" NAG_IFMT "\n\n", "Panel", i);