/* nag_rank_sort (m01dsc) Example Program.
 *
 * Copyright 1990 Numerical Algorithms Group.
 *
 * Mark 4, 1996.
 * Mark 5 revised, 1998.
 * Mark 7 revised, 2001.
 * Mark 8 revised, 2004.
 *
 */

#include <nag.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nag_stddef.h>
#include <nagm01.h>

#ifdef __cplusplus
extern "C"
{
#endif
  static Integer NAG_CALL compare(const Nag_Pointer a, const Nag_Pointer b)
  {
    double x = *((const double *)a);
    double y = *((const double *)b);
    return (x<y ? -1 : (x==y ? 0 : 1));
  }
#ifdef __cplusplus
}
#endif

int main(void)
{
  Integer exit_status=0;
  NagError fail;
  double *vec=0;
  ptrdiff_t step;
  size_t i, n, *rank=0;

  INIT_FAIL(fail);

  /* Skip heading in data file */
  Vscanf("%*[^\n]");
  Vprintf("nag_rank_sort (m01dsc) Example Program Results\n\n");
  Vscanf("%u%u", &n, &step);
  if (n>=1)
    {
      if ( !( vec = NAG_ALLOC(n, double))  ||
           !( rank = NAG_ALLOC(n, size_t)) )
        {
          Vprintf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }
    }
  else
    {
      Vprintf("Invalid n or step.\n");
      exit_status = 1;
      return exit_status;
    }
  for (i=0; i<n; ++i)
    Vscanf("%lf", &vec[i]);
  /* nag_rank_sort (m01dsc).
   * Rank sort of set of values of arbitrary data type
   */
  nag_rank_sort((Pointer) vec, n, step*(ptrdiff_t)(sizeof(double)), compare,
                Nag_Ascending, rank, &fail);
  if (fail.code != NE_NOERROR)
    {
      Vprintf("Error from nag_rank_sort (m01dsc).\n%s\n", fail.message);
      exit_status = 1;
      goto END;
    }
  Vprintf("    Data      Rank\n");
  for (i=0; i<n; ++i)
    Vprintf("   %7.4f   %4u\n", vec[i], rank[i]);
 END:
  if (vec) NAG_FREE(vec);
  if (rank) NAG_FREE(rank);
  return exit_status;
}