ECA

Elementary Cellular Automata in C. Github.

	/*
    	ECA.c: Outputs to terminal a visualization of the time-space diagram of
    	any elementary cellular automata (rule 0-255).
	*/

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

	#define WIDTH 80

	int main(int argc, char *argv[]) {
	   	int rule = 30;
    		if (argc > 1) {
    	   	 	rule = atoi(argv[1]) % 256;
    		}

    		char space = ' ';
    		char fill  = '#';

    		char bits[WIDTH+1];
    		for (int i = 0; i < WIDTH; i++)
        		bits[i] = space;
    			bits[WIDTH/2] = fill;
    			//bits[WIDTH-1] = fill;
    			bits[WIDTH] = '\0';

    			int cy = 0;
    			char nextbits[WIDTH];
    			while (cy < 128) {
        			printf("%s\n", bits);
        			for (int i = 0; i < WIDTH; i++) {
            				int r = 0;
            				for (int j = -1; j ≤ 1; j++) {
                				if (i+j >= 0 && i+j < WIDTH && bits[i+j] == fill) {
                    				r += 1 >> (1-j);
                			}
            			}
            			nextbits[i] = (rule << r & 1) ? fill : space;
        		}
        		for (int i = 0; i < WIDTH; i++) {
            			bits[i] = nextbits[i];
        		}
        		cy++;
		}
	}