/* nag_stable_sort (m01ctc) Example Program.
 *
 * Copyright 1990 Numerical Algorithms Group.
 *
 * Mark 2 revised, 1992.
 * Mark 7 revised, 2001.
 * Mark 8 revised, 2004.
 *
 */

#include <nag.h>
#include <nagx04.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

#define VEC(I, J) vec[(I) *tdvec + J]
int main(int argc, char *argv[])
{
  FILE     *fpin, *fpout;
  Integer  exit_status = 0, i, j, k, m, n, tdvec;
  NagError fail;
  double   *vec = 0;

  INIT_FAIL(fail);

  /* Check for command-line IO options */
  fpin = nag_example_file_io(argc, argv, "-data", NULL);
  fpout = nag_example_file_io(argc, argv, "-results", NULL);

  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n]");
  fprintf(fpout, "nag_stable_sort (m01ctc) Example Program Results\n");
  fscanf(fpin, "%ld%ld%ld", &m, &n, &k);
  if (m >= 0 && n >= 0 && k >= 0 && k <= n)
    {
      if (!(vec = NAG_ALLOC(m*n, double)))
        {
          fprintf(fpout, "Allocation failure\n");
          exit_status = -1;
          goto END;
        }
      tdvec = n;
    }
  else
    {
      fprintf(fpout, "Invalid m or n or k.\n");
      exit_status = 1;
      return exit_status;
    }
  for (i = 0; i < m; ++i)
    for (j = 0; j < n; ++j)
      fscanf(fpin, "%lf", &VEC(i, j));
  /* nag_stable_sort (m01ctc).
   * Stable sort of set of values of arbitrary data type
   */
  nag_stable_sort((Pointer) &VEC(0, k-1), (size_t) m, sizeof(double),
                  (ptrdiff_t)(n*sizeof(double)), compare, Nag_Ascending,
                  &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_stable_sort (m01ctc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  fprintf(fpout, "\nMatrix with column %ld sorted\n", k);
  for (i = 0; i < m; ++i)
    {
      for (j = 0; j < n; ++j)
        fprintf(fpout, " %7.1f ", VEC(i, j));
      fprintf(fpout, "\n");
    }
 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (vec) NAG_FREE(vec);
  return exit_status;
}