#TJHSST ~ Wolfram's One-Dimensional Cellular Automata

wolfram_fast.c

/*
  Wolfram One-Dimensional Cellular Automata
  Fast
*/
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "graphics.h"
#include "conio.h"

#define MAXLEN 320
/* Define the neighorhood -2 -1 0 1 2 */
#define LOWER (-2)
#define UPPER 2

/* 2,4,5 and 2,4 are good ones */
int rules[10]= { 0,0,1,0,1,1,0,0,0,0 };

main()
{
  int old[MAXLEN],new[MAXLEN];
  int time,quit;

  graphics();
  do  {
    for(time=0;time<MAXLEN;time++)
      new[time]=old[time]=random(time+1)%2;
    time=0;
    do  {
      display(old,time);
      process(old,new);
      time++;
      display(new,time);
      process(new,old);
      time++;
    }  while(!kbhit()&&time!=200);
    if(kbhit())
      quit=(getch()==(char)'q');
    else
      quit=0;
    cleardevice();
  }  while(!quit);
}

int neighbors(data,position)
int data[MAXLEN];
int position;
{
  static int oldcnt,farleft;

  if(position==0)  {
    int cnt;
    oldcnt=0;
    for(cnt=LOWER;cnt<=UPPER;cnt++)
      oldcnt+=data[(cnt+MAXLEN)%MAXLEN];
  }
  else  {
    oldcnt-=farleft;
    oldcnt+=data[(position+UPPER)%MAXLEN];
  }
  farleft=data[(position+LOWER+MAXLEN)%MAXLEN];
  return oldcnt;
}

int process(old,new)
int old[MAXLEN],new[MAXLEN];
{
  int position;

  for(position=0;position<MAXLEN;position++)
    new[position]=rules[neighbors(old,position)];
  return 0;
}

int display(data,timestep)
int data[MAXLEN],timestep;
{
  int position;

  for(position=0;position<MAXLEN;position++)  {
    putpixel(position,(190-timestep)%190,data[position]%3+1);
    putpixel(position,195,data[position]%3+1);
  }
  return 0;
}

int graphics()
{
  int gdriver,gmode;

  gdriver=CGA;
  gmode=CGA;
  initgraph(&gdriver,&gmode,"");
  randomize();
}

wolfram_slow.c

/*
  Wolfram One-Dimensional Cellular Automata
  Slow
*/
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "graphics.h"
#include "conio.h"

#define MAXLEN 320
/* Define the neighorhood -2 -1 0 1 2 */
#define LOWER (-2)
#define UPPER 2

/* 2,4,5 and 2,4 are good ones */
int rules[10]= { 0,0,1,0,1,1,0,0,0,0 };

main()
{
  int old[MAXLEN],new[MAXLEN];
  int time,quit;

  graphics();
  do  {
    for(time=0;time<MAXLEN;time++)
      new[time]=old[time]=random(time+1)%2;
    time=0;
    do  {
      display(old,time);
      process(old,new);
      time++;
      display(new,time);
      process(new,old);
      time++;
    }  while(!kbhit()&&time!=200);
    if(kbhit())
      quit=(getch()==(char)'q');
    else
      quit=0;
    cleardevice();
  }  while(!quit);
}

int neighbors(data,position)
int data[MAXLEN];
int position;
{
/*
  static int oldcnt,farleft;

  if(position==0)  {
    int cnt;
    oldcnt=0;
    for(cnt=LOWER;cnt<=UPPER;cnt++)
      oldcnt+=data[(cnt+MAXLEN)%MAXLEN];
  }
  else  {
    oldcnt-=farleft;
    oldcnt+=data[(position+UPPER)%MAXLEN];
  }
  farleft=data[(position+LOWER+MAXLEN)%MAXLEN];
  return oldcnt;
*/
  int cnt=0,cnt2;

  for(cnt2=LOWER;cnt2<=UPPER;cnt2++)
    cnt+=data[(position+cnt2+MAXLEN)%MAXLEN];
  return cnt;
}

int process(old,new)
int old[MAXLEN],new[MAXLEN];
{
  int position;

  for(position=0;position<MAXLEN;position++)
    new[position]=rules[neighbors(old,position)];
  return 0;
}

int display(data,timestep)
int data[MAXLEN],timestep;
{
  int position;

  for(position=0;position<MAXLEN;position++)
    putpixel(position,200-timestep,data[position]%3+1);
  return 0;
}

int graphics()
{
  int gdriver,gmode;

  gdriver=CGA;
  gmode=CGA;
  initgraph(&gdriver,&gmode,"");
  randomize();
}

Two C programs found on an old 5.25 floppy disk from when I was a nerd at Thomas Jefferson High School for Science and Technology between 1988 and 1992.

These program implement Wolfram's one-dimensional cellular automata.

http://en.wikipedia.org/wiki/Elementary_cellular_automaton

Anyone can do whatever they'd like to with this program--if anything.

I am now a two-dimensional nerd.