/* collatz.c -- explore the Collatz conjecture in C */
/* Note:  For motivation, see the Wikipedia entry for the Collatz conjecture */

#include <stdio.h>

int main() {
    int i = 27; /* a particularly bad initial value of i */

    /* if Collatz is right, this loop terminates for any initial value of i */
    while (i != 1) {
	printf( "%d\n", i );
	if ((i & 1) == 1) { /* i is odd */
	    i = i*3 + 1;
	} else { /* i is even */
	    i = i >> 1; /* same as i/2 */
	}
    }
    printf( "%d\n", i );
    return 0;
}