Question

For the recursive factorial function output shown below, which lines of output would reflect the backward phase? 1 factorial(3) 2 3 * factorial(2) 3 3 * 2 * factorial(1) 4 3 * 2 * 1 5 3 * 2 6 6 (1 point) Responses 1,2,3 1,2,3 1,4 1,4 4,5,6 4,5,6 1,2,3,4,5,6

Answer 1

To determine which lines of output reflect the backward phase of the recursive factorial function, we need to understand how the recursion works:

1. **Forward Phase**: This is when the recursive calls are being made. In this phase, the function calls itself with decremented values (n-1) until it reaches the base case (typically factorial(1) or factorial(0)).

2. **Backward Phase**: This is when the function starts returning values back through the recursion, multiplying the results together as it unwinds the stack of calls.

From the provided outputs:

- **Lines 1, 2, and 3** are part of the forward phase as they are making recursive calls.
- **Lines 4, 5, and 6** represent the backward phase where the multiplication results start being calculated and returned.

Therefore, the lines of output that reflect the backward phase would be **4, 5, 6**.

So the correct response is **4,5,6**.