Question

def factorial(n):

space = ' ' * (4 * n)

print(space, 'factorial', n)

if n == 0:

print(space, 'returning 1')

return 1

else:

recurse = factorial(n-1)

result = n * recurse

print(space, 'returning', result)

return result

space is a string of space characters that controls the indentation of the output. Here is the

result of factorial(4) :

factorial 4

factorial 3

factorial 2

factorial 1

factorial 0

returning 1

returning 1

returning 2

returning 6

returning 24

If you are confused about the flow of execution, this kind of output can be helpful. It takes

"Debugging" lists three possibilities to consider if a function is not working.

• Describe each possibility in your own words.
• Define "precondition" and "postcondition" as part of your description.
• Create your own example of each possibility in Python code. List the code for each example, along with sample output from trying to run it.

Answer 1

Please read the link below, explained here in detail:

https://www.python-course.eu/python3_recursive_functions.php