#include <stdio.h>

#define MaxSIZE 1000 
double drand48();
int rules[8];
int width;


int curr[MaxSIZE+2];
int next[MaxSIZE+2];

/***********************************/
void fill_in_rule(int rule) {
  int i;
  unsigned int foo = rule;
  for( i=0; i<8; i++ ) {
    rules[i] = foo & 1;
    foo = foo >> 1;
  }
}
/***********************************/
void make_periodic() {
  curr[0] = curr[width];
  curr[width+1] = curr[1];
}
/***********************************/
void initialize(int type) {
  int i;
  if( type == 0 ) {
    for( i=1; i<=width; i++ ) 
      curr[i] = (drand48() > .5);
  }
  make_periodic();
}
/***********************************/
void update() {
  int i;
  unsigned int state;
  for( i=1; i<=width; i++ ) {
    state=0;
    /* this is arranged so we read the state from left to right, i.e. 110 is 3 */
    if( curr[i-1] == 1 )
      state = 4;
    if( curr[i] == 1 )
      state += 2;
    if( curr[i+1] == 1 )
      state += 1;
 
    next[i] = rules[state];
  }

  for( i=1; i<=width; i++ )
    curr[i] = next[i];
  
  make_periodic();
}    
/****************************************/
void display_state() {
  int i;
  for( i=1; i<=width; i++ ) {
    if( curr[i] == 1 )
      printf("@");
    else
      printf(" ");
  }
  printf("\n");
}

/****************************************/


int main( int argc, char **argv) {
  int i,j,k;
  int nsteps = 20;
  char c='a';
  int rule = 34;
  int randomstart=1;
  int seed=934;
  int sleeptime=0;
  width = 80;

  if( argc < 2 ) {
    fprintf(stderr,"Syntax: $s rule [nsteps [seed [width] ]] \n",argv[0]);
    fprintf(stderr,"rule: one of the CA rules\n");
    fprintf(stderr,"nsteps: how many steps to run\n");
    fprintf(stderr,"seed: random seed.\n");
    fprintf(stderr,"width: number of elements (less than MaxSIZE).\n");
    exit(0);
  }

  rule = atoi(argv[1]);
  fill_in_rule(rule);

  for( i=7;i>=0;i-- )
    printf("%d",rules[i]);
  printf("\n");
  
  if( argc > 2 )
    nsteps = atoi(argv[2]);
  if( nsteps == 0 ) 
    nsteps = 20;

  if( argc > 3 )
    seed = atoi(argv[3]);

  if( seed == 0 )
    seed = 983;

  if( argc > 4 )
    width = atoi(argv[4]);
  if( width == 0 ) width = 80;
  if( width > MaxSIZE ) width = MaxSIZE;

  srand48(seed); /* seed the random number generator */


  initialize(0);

  for( i=0; i<nsteps; i++ ) {
    display_state();
    update();
    sleep(sleeptime);
  }
}