/* nag_bivariate_students_t (g01hcc) Example Program.
 *
 * Mark 23 Release. NAG Copyright 2011.
 */
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagg01.h>

int main(void)
{
  /* Scalars */
  Integer             df, exit_status = 0, ierr;
  double              prob, rho;
  /* Arrays */
  char                nag_enum_arg[14];
  double              a[2], b[2];
  /* NAG types */
  Nag_TailProbability tail;
  NagError           fail;

  printf("%s\n\n",
          "nag_bivariate_students_t (g01hcc) Example Program Results");

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

  /* Display headers */
  printf("%-8s%2s%-8s%2s%-8s%2s%-8s%2s%-4s%2s%-8s%2s%-14s%2s%-8s\n\n",
          "a1", " ", "b1", " ", "a2", " ", "b2", " ", "df", " ", "rho", " ",
          "Tail", " ",  "p");

  while (1)
  {
    ierr = scanf("%14s", nag_enum_arg);
    if (ierr == EOF || ierr < 1)
    {
        break;
    }

    /* Initialize limits */
    a[0] = a[1] = b[0] = b[1] = 0.0;

    /* nag_enum_name_to_value(x04nac).
     * Converts NAG enum member name to value
     */
    tail = (Nag_TailProbability)nag_enum_name_to_value(nag_enum_arg);

    /* Read parameter values*/
    switch (tail)
    {
    case Nag_LowerTail:
        scanf("%ld%lf%lf%lf", &df, &rho, b, b+1);
        break;
    case Nag_Central:
        scanf("%ld%lf%lf%lf%lf%lf", &df, &rho, a, b, a+1, b+1);
        break;
    case Nag_UpperTail:
        scanf("%ld%lf%lf%lf", &df, &rho, a, a+1);
        break;
    default:
        printf(" %s\n", "Invalid tail specification in data file");
        exit_status = -1;
        goto END;
    }

    scanf("%*[^\n]");

    /* Calculate probablity for the bivariate Student's t-distribution */
    INIT_FAIL(fail);
    /* nag_bivariate_students_t (g01hcc) */
    prob = nag_bivariate_students_t(tail, a, b, df, rho, &fail);

    /* Display results */
    switch (tail)
    {
    case Nag_LowerTail:
        printf("%-8s%2s%-8g%2s%-8s%2s%-8g",
                "-Inf", " ", b[0], " ", "-Inf", " ", b[1]);
        break;
    case Nag_Central:
        printf("%-8g%2s%-8g%2s%-8g%2s%-8g",
                a[0], " ", b[0], " ", a[1], " ", b[1]);
        break;
    case Nag_UpperTail:
        printf("%-8g%2s%-8s%2s%-8g%2s%-8s",
                a[0], " ", "Inf", " ", a[1], " ", "Inf");
    }

    printf("%2s%-4ld%2s%-8g%2s%-14s%2s%-8.4f\n",
            " ", df, " ", rho, " ", nag_enum_arg, " ", prob);
  }

  END:
  return exit_status;
}