#include <stdio.h>
#include <stdlib.h>
#include <memory.h>

 int
 main( int argc, char *argv[] )
 {
     /* variables */
     FILE *fp_node  = NULL;
     FILE *fp_coord = NULL;
     FILE *fp_time  = NULL;

     int     i = 0;
     int     j = 0;
     int     k = 0;
     int     n = 0;

     static int     i_max = 10;
     static int     j_max = 15;
     static int     k_max = 20;
     static int     n_max = 12;

     size_t ijk_max = 0;
     int     index  = 0;

     float   u = 0;
     float   v = 0;
     float *u_value =NULL;
     float *v_value =NULL;

     float   x = 0;
     float   y = 0;
     float   z = 0;
     float *coord_value =NULL;

     /* function */
     ijk_max = (size_t)(i_max * j_max * k_max );
     /* open file */
     fp_node  = fopen("sample_node.dat",  "w");
     fp_coord = fopen("sample_coord.dat", "w");
     fp_time  = fopen("sample_time.dat",  "w");
     /* alloc memory */
     coord_value = (float *)malloc( sizeof(float) * ijk_max * 3);
     u_value = (float *)malloc( sizeof(float) * ijk_max);
     v_value = (float *)malloc( sizeof(float) * ijk_max);
     for( n =0;n<n_max;n++)
     {
         fprintf(fp_time, "step_%04d\n",n);
         for(k=0;k<k_max;k++)
         {
             for(j=0;j<j_max;j++)
             {
                 for(i=0;i<i_max;i++)
                 {
                     x  = (float)i * 6.0;
                     y  = (float)j * 4.0;
                     z  = (float)k * 3.0;
                     u  = (float)(i+j+k-n);
                     v  = (float)(i+j-k+n);

                     index = i+j*i_max+k*i_max*j_max;

                     coord_value[index*3]   = x;
                     coord_value[index*3+1] = y;
                     coord_value[index*3+2] = z;

                     u_value[i+j*i_max+k*i_max*j_max] = u;
                     v_value[i+j*i_max+k*i_max*j_max] = v;
                 }
             }
         }
         fwrite( coord_value, sizeof(float),ijk_max*3 , fp_coord);
         fwrite( u_value, sizeof(float), ijk_max, fp_node);
         fwrite( v_value, sizeof(float), ijk_max, fp_node);
     }
     /* free memory */
     free( coord_value );
     free( u_value );
     free( v_value );
     /* close file */
     fclose(fp_node);
     fclose(fp_coord);
     fclose(fp_time);
     return(1);
 }