/// Prints a countdown from n to 1, then Liftoff.
void countdown(int n) {
    if (n <= 0) {
        IO.println("Liftoff.");
        return;
    }
    IO.println(n);
    countdown(n - 1);
}

void main() {
    countdown(3);
}

// From Groundwork, chapter 12 (ch12-recursion-and-problem-solving), box 6.
// This example is from Groundwork, licensed CC BY-NC-SA 4.0.
// Run with: java ch12_06.java