}
	}

	ret = stk[sp];
	free(stk);
	return ret;
}

int main() {
	printf("gcd(27,15): %d\n", gcd(27,15));
	printf("gcd(12,18): %d\n", gcd(12,18));
	printf("gcd(13,19): %d\n", gcd(13,19));

	printf("gcd_stk(27,15): %d\n", gcd_stk(27,15));
	printf("gcd_stk(12,18): %d\n", gcd_stk(12,18));
	printf("gcd_stk(13,19): %d\n", gcd_stk(13,19));

	return 0;
}
</pre>

<pre id="code_file_system">
// Copyright 2016 ChaiShushan &lt;chaishushan{AT}gmail.com&gt;. All rights reserved.
// Use of this sourc