Exam-style question
Try this first
A subroutine calls itself recursively. Why can separate stack frames be needed for the different calls?.
- A.Each call has its own return address, parameters and local variables
- B.Only the first call needs a stack frame; later calls share all its data
- C.Recursive calls do not use stack frames
- D.A new frame is created only when a parameter has no value
Model answer
What a good answer should say
- Each call has its own return address, parameters and local variables
Explanation
Why this works
Each recursive call is a separate active subroutine call. Its stack frame preserves its own data and return location, so the calls can later return in the correct order.
Common mistake
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