Example description
/* nag_mesh2d_inc (d06aac) Example Program.
 *
 * Copyright 2017 Numerical Algorithms Group.
 *
 * Mark 26.2, 2017.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nagd06.h>

#define EDGE(I, J) edge[3*((J) -1)+(I) -1]
#define CONN(I, J) conn[3*((J) -1)+(I) -1]
#define COOR(I, J) coor[2*((J) -1)+(I) -1]

int main(void)
{
  const Integer nvmax = 250;
  double coef, power;
  Integer exit_status, i1, i, itrace, k, nedge, nelt, nv, nvb, reftk;
  Nag_Boolean smooth;
  NagError fail;
  char pmesh[2];
  double *bspace = 0, *coor = 0;
  Integer *conn = 0, *edge = 0;

  INIT_FAIL(fail);

  exit_status = 0;

  printf("nag_mesh2d_inc (d06aac) Example Program Results\n\n");

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

  /* Reading of the geometry */
  scanf("%" NAG_IFMT "%" NAG_IFMT "%*[^\n] ", &nvb, &nedge);

  if (nvb > nvmax) {
    printf("Problem with the array dimensions\n");
    printf(" nvb nvmax %6" NAG_IFMT "%6" NAG_IFMT "\n", nvb, nvmax);
    printf(" Please increase the value of nvmax\n");
    exit_status = -1;
    goto END;
  }

  /* Allocate memory */

  if (!(bspace = NAG_ALLOC(nvb, double)) ||
      !(coor = NAG_ALLOC(2 * nvmax, double)) ||
      !(conn = NAG_ALLOC(3 * (2 * nvmax - 1), Integer)) ||
      !(edge = NAG_ALLOC(3 * nedge, Integer)))
  {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  /* Coordinates of the boundary mesh vertices and boundary edges */

  for (i = 1; i <= nvb; ++i) {
    scanf("%" NAG_IFMT "", &i1);
    scanf("%lf", &COOR(1, i));
    scanf("%lf", &COOR(2, i));
    scanf("%*[^\n] ");
  }

  for (i = 1; i <= nedge; ++i) {
    scanf("%" NAG_IFMT "", &i1);
    scanf("%" NAG_IFMT "", &EDGE(1, i));
    scanf("%" NAG_IFMT "", &EDGE(2, i));
    scanf("%" NAG_IFMT "", &EDGE(3, i));
    scanf("%*[^\n] ");
  }
  scanf(" ' %1s '%*[^\n]", pmesh);

  /* Initialize mesh control parameters */

  for (i = 0; i < nvb; ++i)
    bspace[i] = 0.05;

  smooth = Nag_TRUE;
  itrace = 0;
  coef = 0.75;
  power = 0.25;

  /* Call to the mesh generator */

  /* nag_mesh2d_inc (d06aac).
   * Generates a two-dimensional mesh using a simple
   * incremental method
   */
  nag_mesh2d_inc(nvb, nvmax, nedge, edge, &nv, &nelt, coor, conn, bspace,
                 smooth, coef, power, itrace, 0, &fail);

  if (fail.code == NE_NOERROR) {
    if (pmesh[0] == 'N') {
      printf(" nv   =%6" NAG_IFMT "\n", nv);
      printf(" nelt =%6" NAG_IFMT "\n", nelt);
    }
    else if (pmesh[0] == 'Y') {
      /* Output the mesh to view it using the NAG Graphics Library */

      printf(" %10" NAG_IFMT "%10" NAG_IFMT "\n", nv, nelt);

      for (i = 1; i <= nv; ++i)
        printf("  %15.6e  %15.6e\n", COOR(1, i), COOR(2, i));

      reftk = 0;
      for (k = 1; k <= nelt; ++k) {
        printf(" %10" NAG_IFMT "%10" NAG_IFMT "%10" NAG_IFMT "%10" NAG_IFMT
               "\n", CONN(1, k), CONN(2, k), CONN(3, k), reftk);
      }
    }
    else {
      printf("Problem with the printing option Y or N\n");
      exit_status = -1;
      goto END;
    }
  }
  else {
    printf("Error from nag_mesh2d_inc (d06aac).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

END:
  NAG_FREE(bspace);
  NAG_FREE(coor);
  NAG_FREE(conn);
  NAG_FREE(edge);

  return exit_status;
}