NAG Library Manual, Mark 27.2
```/* nag_nonpar_test_wilcoxon (g08agc) Example Program.
*
* Copyright 2021 Numerical Algorithms Group.
*
* Mark 27.2, 2021.
*/

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

int main(void) {
Integer exit_status = 0, i, n, non_zero;
NagError fail;
double *data = 0, median, p, w, *x = 0, *y = 0, z;

INIT_FAIL(fail);

printf("nag_nonpar_test_wilcoxon (g08agc) Example Program Results");

/* Skip heading in data file */
scanf("%*[^\n]");
scanf("%" NAG_IFMT "", &n);
if (!(x = NAG_ALLOC(n, double)) || !(y = NAG_ALLOC(n, double)) ||
!(data = NAG_ALLOC(n, double))) {
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

for (i = 1; i <= n; ++i)
scanf("%lf", &x[i - 1]);

for (i = 1; i <= n; ++i)
scanf("%lf", &y[i - 1]);

printf("\n\n");
printf("%s\n", "Wilcoxon one sample signed ranks test");
printf("\n");
printf("%s", "Data values\n");
for (i = 1; i <= n; ++i)
printf("%5.1f%s", x[i - 1], i % 8 ? "" : "\n");
for (i = 1; i <= n; ++i)
printf("%5.1f%s", y[i - 1], i % 8 ? "" : "\n");

for (i = 1; i <= n; ++i)
data[i - 1] = x[i - 1] - y[i - 1];
median = 0.0;
/* nag_nonpar_test_wilcoxon (g08agc).
* Performs the Wilcoxon one-sample (matched pairs) signed
* rank test
*/
nag_nonpar_test_wilcoxon(n, data, median, Nag_TwoTail, Nag_IncSignZerosN, &w,
&z, &p, &non_zero, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_nonpar_test_wilcoxon (g08agc).\n%s\n", fail.message);
exit_status = 1;
goto END;
}

printf("\n\n");
printf("%s%8.4f\n", "Test statistic            = ", w);
printf("%s%8.4f\n", "Normalized test statistic = ", z);
printf("%s%8" NAG_IFMT "\n", "Degrees of freedom        = ", non_zero);
printf("%s%8.4f\n", "Two tail probability      = ", p);

END:
NAG_FREE(x);
NAG_FREE(y);
NAG_FREE(data);
return exit_status;
}
```