Question

Section 6.9 of your textbook ("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

Precondition: n >= 0
Postcondition: The factorial of value (n) is returned
'''
def factorial(n):
    if(n < 0) :
        print('the precodition is violated')
        return

    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

factorial(5)