NAG Library Manual, Mark 27.3
Interfaces:  FL   CL   CPP   AD 

NAG CL Interface Introduction
Example description
/* nag_specfun_gamma_incomplete (s14bac) Example Program.
 *
 * Copyright 2021 Numerical Algorithms Group.
 *
 * Mark 27.3, 2021.
 */

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

int main(void) {
  Integer exit_status = 0;
  double a, p, q, tol, x;
  NagError fail;

  INIT_FAIL(fail);

  /* Skip heading in data file */
  scanf("%*[^\n]");
  printf("nag_specfun_gamma_incomplete (s14bac) Example Program Results\n");
  /* nag_machine_precision (x02ajc).
   * The machine precision
   */
  tol = nag_machine_precision;
  printf("        a           x           p           q\n");
  while (scanf("%lf %lf", &a, &x) != EOF)
  {
    /* nag_specfun_gamma_incomplete (s14bac).
     * Incomplete Gamma functions P(ax) and Q(ax)
     */
    nag_specfun_gamma_incomplete(a, x, tol, &p, &q, &fail);
    if (fail.code != NE_NOERROR) {
      printf("Error from nag_specfun_gamma_incomplete (s14bac).\n%s\n",
             fail.message);
      exit_status = 1;
      goto END;
    }
    printf("%12.4f%12.4f%12.4f%12.4f\n", a, x, p, q);
  }

END:
  return exit_status;
}