What is displayed after running this program?

Steps to Solve

1. Initial Function Call The function fib is called with parameters $x = 0$ and $y = 1$.

2. First Condition Check The first condition checks if $x < 5$. Since $0 < 5$ is true, we proceed to the recursive call.

3. First Recursive Call Invoke fib(y, x + y) which translates to fib(1, 0 + 1), resulting in fib(1, 1).

4. Next Condition Check Now, with $x = 1$ and $y = 1$, we check again if $x < 5$. Since $1 < 5$ is true, make another recursive call.

5. Second Recursive Call Invoke fib(1, 1 + 1), resulting in fib(1, 2).

6. Next Condition Check With $x = 1$ and $y = 2$, check if $x < 5$. $1 < 5$ is still true, make another call.

7. Third Recursive Call Invoke fib(2, 1 + 2), resulting in fib(2, 3).

8. Next Condition Check With $x = 2$ and $y = 3$, check if $x < 5$. Since $2 < 5$ is true, make another call.

9. Fourth Recursive Call Invoke fib(3, 2 + 3), resulting in fib(3, 5).

10. Next Condition Check With $x = 3$ and $y = 5$, check if $x < 5$. Since $3 < 5$ is true, make another call.

11. Fifth Recursive Call Invoke fib(4, 3 + 5), resulting in fib(4, 8).

12. Next Condition Check With $x = 4$ and $y = 8$, check if $x < 5$. $4 < 5$ is true, call again.

13. Sixth Recursive Call Invoke fib(5, 4 + 8), resulting in fib(5, 12).

14. Final Condition Check Now, with $x = 5$, check if $x < 5$. Since $5 < 5$ is false, the recursion ends.

15. Print Execution Begins We now begin to return from the recursion and print the value of $y$:

• From fib(5, 12) nothing is printed yet.
• From fib(4, 8): print $8$.
• From fib(3, 5): print $5$.
• From fib(2, 3): print $3$.
• From fib(1, 2): print $2$.
• From fib(0, 1): print $1$.

Thus, the output will be printed in reverse order.