```/* nag_shapiro_wilk_test (g01ddc) Example Program.
*
* Copyright 2017 Numerical Algorithms Group.
*
* Mark 26.1, 2017.
*
*/

#include <nag.h>
#include <nag_stdlib.h>
#include <stdio.h>
#include <nagg01.h>
#include <nagm01.h>

int main(void)
{

/* Local variables */
Nag_Boolean calwts;
Integer exit_status = 0, i, j, n;
NagError fail;
double *a = 0, pw, w, *x = 0;

INIT_FAIL(fail);

printf("nag_shapiro_wilk_test (g01ddc) Example Program Results\n");

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

calwts = Nag_TRUE;
scanf("%" NAG_IFMT " ", &n);
if (n >= 3) {
if (!(a = NAG_ALLOC(n, double)) || !(x = NAG_ALLOC(n, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
}
else {
printf("Invalid n.\n");
exit_status = 1;
return exit_status;
}
for (j = 1; j <= 2; ++j) {
for (i = 1; i <= n; ++i)
scanf("%lf ", &x[i - 1]);

/* nag_double_sort (m01cac).
* Quicksort of set of values of data type double
*/
nag_double_sort(x, (size_t) n, Nag_Ascending, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_double_sort (m01cac).\n%s\n", fail.message);
exit_status = 1;
goto END;
}
/* nag_shapiro_wilk_test (g01ddc).
* Shapiro and Wilk's W test for Normality
*/
nag_shapiro_wilk_test(n, x, calwts, a, &w, &pw, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_shapiro_wilk_test (g01ddc).\n%s\n",
fail.message);
exit_status = 1;
goto END;
}

printf("\n For sample number %2" NAG_IFMT ", value of W statistic = "
"%7.4f\n", j, w);
printf("                       Significance level is %8.4f\n", pw);
calwts = Nag_FALSE;
}
END:
NAG_FREE(a);
NAG_FREE(x);
return exit_status;
}
```