Fizz Buzz on State Machine with States Hardcoded

fizzbuzz_machine_hardcoded.c

/*
 * Brian Chrzanowski
 * Mon May 06, 2019 23:41
 *
 * This was a meme. A friend of mine thought about how you could do fizz-buzz
 * as a 15(ish) state machine.
 *
 * I think my thing is closer to a circular linked list with function pointers,
 * but that's whatever.
 *
 * He got mad that I didn't hardcode my state machine, so this version's for him.
 */

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

#define USAGE "%s <num>\n"

struct state_t {
	void (*func) (char *);
	int next;
};

void fizz(char *s)
{
	printf("fizz\n");
}

void buzz(char *s)
{
	printf("buzz\n");
}

void fizzbuzz(char *s)
{
	printf("fizz buzz\n");
}

void pnum(char *s)
{
	printf("%s\n", s);
}

// our machine state is hardcoded into the binary :)
struct state_t machine[15] = {
	{pnum, 1},
	{pnum, 2},
	{fizz, 3},
	{pnum, 4},
	{buzz, 5},
	{fizz, 6},
	{pnum, 7},
	{pnum, 8},
	{fizz, 9},
	{buzz, 10},
	{pnum, 11},
	{fizz, 12},
	{pnum, 13},
	{pnum, 14},
	{fizzbuzz, 0}
};

int main(int argc, char **argv)
{
	struct state_t *curr;
	int i, c, maxnum;
	char buf[32];

	if (argc < 2) {
		fprintf(stderr, USAGE, argv[0]);
		return 1;
	}

	maxnum = atoi(argv[1]);

	// execute the machine
	for (curr = machine, i = 1; i < maxnum; i++, curr = &machine[curr->next]) {
		snprintf(buf, sizeof(buf), "%d", i);
		printf("%d\t", i);
		curr->func(buf);
	}

	return 0;
}