#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>

int main(int argc, char* argv[])
{
  /* Exit if # of arguments < 2 */
  if (argc < 3) {
    printf("Usage: %s <Ndim> <Niter>\n",argv[0]);
    exit(1);
  }

  int N=atoi(argv[1]);
  int Niter=atoi(argv[2]);

  int x,n,max=0;
  double sum=0;

  int *tmp;
  int *buffer = (int*)malloc(N * sizeof(int));
  int *nextbuffer = (int*)malloc(N * sizeof(int));
  
  printf("\nSize of the array:    %d\n",N);
  printf("Number of iterations: %d\n\n",Niter);

  /* Initialize the array. */
  for (x=0; x<N; x++) {
    buffer[x]=x%10;
  }

  /* Main loop */
  for (n=0; n < Niter; n++) {
    for (x=0; x<N; x++) {
      nextbuffer[x]=(buffer[(x-1+N)%N]+buffer[(x+1)%N])%10;
    }
    /* Swap the pointers. */
    tmp=buffer; buffer=nextbuffer; nextbuffer=tmp;
  }

  /* Find the maximum and average. */
  for (x=0;x<N;x++) {
    sum += buffer[x];
    if (buffer[x]>max)
      max=buffer[x];
  }

  printf("Maximum: %d\n",max);
  printf("Average: %f\n\n",sum/(double)N);

  free(buffer);
  free(nextbuffer);

}