Answer to Question #275291 in Python for solokin

Question

• 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

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

print(factorial(7))

Adding print statements at the beginning and end of a function can help make the flow of execution more visible. For example, here is a version of factorial with print statements.

test.py
                             factorial 7
                         factorial 6
                     factorial 5
                 factorial 4
             factorial 3
         factorial 2
     factorial 1
 factorial 0
 returning 1
     returning 1
         returning 2
             returning 6
                 returning 24
                     returning 120
                         returning 720
                             returning 5040
5040

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

If You are confused about the flow of execution, this kind of output can be helpful. It takes some time to develop effective scaffolding*, but a little bit of scaffolding can save a lot of debugging.

Scaffolding, as used in computing, refers to one of two techniques: The first is a code generation technique related to database access in some model view controller frameworsk;

the second is a project generation technique supported by various tools.