```/* nag_gamma_pdf_vector (g01kkc) Example Program.
*
* Copyright 2017 Numerical Algorithms Group.
*
* Mark 26.2, 2017.
*/
#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagg01.h>

int main(void)
{
/* Integer scalar and array declarations */
Integer lx, la, lb, i, lout;
Integer *ivalid = 0;
Integer exit_status = 0;

/* NAG structures */
NagError fail;
Nag_Boolean ilog;

/* Double scalar and array declarations */
double *x = 0, *a = 0, *b = 0, *pdf = 0;

/* Character scalar and array declarations */
char cilog[40];

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

printf("nag_gamma_pdf_vector (g01kkc) Example Program Results\n\n");

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

/* Read in the flag indicating whether logs are required */
scanf("%39s%*[^\n] ", cilog);
ilog = (Nag_Boolean) nag_enum_name_to_value(cilog);

/* Read in the input vectors */
scanf("%" NAG_IFMT "%*[^\n] ", &lx);
if (!(x = NAG_ALLOC(lx, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
for (i = 0; i < lx; i++)
scanf("%lf", &x[i]);
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%*[^\n] ", &la);
if (!(a = NAG_ALLOC(la, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
for (i = 0; i < la; i++)
scanf("%lf", &a[i]);
scanf("%*[^\n] ");
scanf("%" NAG_IFMT "%*[^\n] ", &lb);
if (!(b = NAG_ALLOC(lb, double)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}
for (i = 0; i < lb; i++)
scanf("%lf", &b[i]);
scanf("%*[^\n] ");

/* Allocate memory for output */
lout = MAX(lx, MAX(la, lb));
if (!(pdf = NAG_ALLOC(lout, double)) ||
!(ivalid = NAG_ALLOC(lout, Integer)))
{
printf("Allocation failure\n");
exit_status = -1;
goto END;
}

/* Calculate probability */
nag_gamma_pdf_vector(ilog, lx, x, la, a, lb, b, pdf, ivalid, &fail);
if (fail.code != NE_NOERROR) {
printf("Error from nag_gamma_pdf_vector (g01kkc).\n%s\n", fail.message);
exit_status = 1;
if (fail.code != NW_IVALID)
goto END;
}

/* Display title */
printf("   x          a         b        pdf      ivalid\n");
printf(" ------------------------------------------------\n");

/* Display results */
for (i = 0; i < lout; i++)
printf("%6.2f    %6.2f    %6.2f    %9.3e    %3" NAG_IFMT "\n",
x[i % lx], a[i % la], b[i % lb], pdf[i], ivalid[i]);

END:
NAG_FREE(x);
NAG_FREE(a);
NAG_FREE(b);
NAG_FREE(pdf);
NAG_FREE(ivalid);

return (exit_status);
}
```