/* nag_fft_complex(c06ecc) Example Program
 *
 * Copyright 1990 Numerical Algorithms Group.
 *
 * Mark 1, 1990.
 */

#include <nag.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nagc06.h>

#define NMAX 20

int main(void)
{
  Integer j, n ;
  double x[NMAX], y[NMAX], xx[NMAX], yy[NMAX];

  Vprintf("c06ecc Example Program Results\n");
  /* Skip heading in data file */
  Vscanf("%*[^\n]");
  while (scanf("%ld", &n)!=EOF)
    if (n>1 && n<=NMAX)
      {
        for (j = 0; j<n; ++j)
          {
            Vscanf("%lf%lf", &x[j], &y[j]);
            xx[j] = x[j];
            yy[j] = y[j];
          }
        /* Compute transform */
        c06ecc(n, x, y, NAGERR_DEFAULT);
        Vprintf("\nComponents of discrete Fourier transform\n\n");
        Vprintf("         Real       Imag\n\n");
        for (j = 0; j<n; ++j)
          Vprintf("%3ld %10.5f %10.5f\n", j, x[j], y[j]);
        /* Compute inverse transform */
        /* Conjugate the transform */
        c06gcc(n, y, NAGERR_DEFAULT);
        /* Transform */
        c06ecc(n, x, y, NAGERR_DEFAULT);
        /* Conjugate to give inverse transform */
        c06gcc(n, y, NAGERR_DEFAULT);
        Vprintf("\nOriginal sequence as restored by inverse transform\n");
        Vprintf("\n             Original                  Restored\n");
        Vprintf("         Real       Imag           Real       Imag\n\n");
        for (j = 0; j<n; ++j)
          Vprintf("%3ld %10.5f %10.5f     %10.5f %10.5f\n",
                  j, xx[j], yy[j], x[j], y[j]);
      }
    else
      {
        Vfprintf(stderr,"\n Invalid value of n\n");
        return EXIT_FAILURE;
      }
  return EXIT_SUCCESS;
}