/* nag_1d_quad_vals (d01gac) Example Program.
 *
 * Copyright 1991 Numerical Algorithms Group.
 *
 * Mark 2, 1991.
 * Mark 8 revised, 2004.
 */

#include <nag.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nagd01.h>

int main(void)
{

  Integer exit_status=0, i, n;
  NagError fail;
  double ans, error, *x=0, *y=0;

  INIT_FAIL(fail);
  Vprintf("nag_1d_quad_vals (d01gac) Example Program Results\n");
  Vscanf("%*[^\n]");    /* Skip heading in data file */
  Vscanf("%ld",&n);
  if (n>=4)
    {
      if ( !( x = NAG_ALLOC(n, double)) ||
           !( y = NAG_ALLOC(n, double))  )
        {
          Vprintf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }
    }
  else
    {
      Vprintf("Invalid n.\n");
      exit_status = 1;
      return exit_status;
    }
  for (i=0; i < n; ++i)
    Vscanf("%lf%lf", &x[i], &y[i]);
  /* nag_1d_quad_vals (d01gac).
   * One-dimensional integration of a function defined by data
   * values only
   */
  nag_1d_quad_vals(n, x, y, &ans, &error, &fail);
  if (fail.code == NE_NOERROR)
    {
      Vprintf("Integral = %7.4f\n", ans);
      Vprintf("Estimated error = %7.4f\n", error);
    }
  else
    {
      Vprintf("Error from nag_1d_quad_vals (d01gac).\n%s\n", fail.message);
      Vprintf("%s\n", fail.message);
      exit_status = 1;
    }
 END:
  if (x) NAG_FREE(x);
  if (y) NAG_FREE(y);
  return exit_status;
}