/* nag_zeros_cubic_real (c02akc) Example Program.
 *
 * Copyright 2021 Numerical Algorithms Group.
 *
 * NAG C Library
 *
 * Mark 27.2, 2021.
 */

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

int main(void) {
  double *errest = 0, *zeroi = 0, *zeror = 0;
  double r, s, t, u;
  Integer i;
  Integer exit_status = 0;
  NagError fail;

  INIT_FAIL(fail);

  printf("nag_zeros_cubic_real (c02akc) Example Program Results\n\n");

  if (!(errest = NAG_ALLOC(3, double)) || !(zeroi = NAG_ALLOC(3, double)) ||
      !(zeror = NAG_ALLOC(3, double))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  /* Skip heading in data file */
  scanf("%*[^\n] ");
  scanf("%lf %lf %lf %lf ", &u, &r, &s, &t);

  /* nag_zeros_cubic_real (c02akc).
   * Zeros of a cubic polynomial with real coefficients
   */
  nag_zeros_cubic_real(u, r, s, t, zeror, zeroi, errest, &fail);
  if (fail.code == NE_NOERROR) {
    printf("\n Roots of cubic equation             Error estimates\n");
    printf("                                   (machine-dependent)\n\n");
    for (i = 0; i <= 2; ++i) {
      printf(" z = %10.5f %10.5f%s         %g\n", zeror[i], zeroi[i], "*i",
             errest[i]);
    }
  } else {
    printf("Error from nag_zeros_cubic_real (c02akc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

END:
  NAG_FREE(errest);
  NAG_FREE(zeroi);
  NAG_FREE(zeror);
  return exit_status;
}