C code implementing Singe's Fear Uncertainty and Doubt protocol

fud.c

#include <stdio.h>

int main() {
    int i, n, m ;
    scanf("%d", &n);
	int o = n;
    while ( n - o < 999999999 ) {
		char c = '2';
		if ((n%3) == 0) {
            c = '0';
		} else if ((n%5) == 0) {
            c = '1';
		} else {
			i = n;
	   		while (i) {
				m = i % 10;
				if (m == 3) {
					c = '0';
					break;
				} else if (m == 5) {
					c = '1';
					// break;
				}
				i /= 10;
			}
		}

		putchar(c);

		n++;
    }
    return 0;
}