Algorithms For Dummies

  Performing Essential Data Manipulations Using Python 

     107

def factorial(n):

    print("factorial called with n = ", str(n))

    result = 1

    while n > 1:

        result = result * n

        n = n - 1

        print("Current value of n is ", str(n))

    print("Ending condition met.")

    return result

  

print(factorial(5))

  

factorial called with n =  5

Current value of n is  4

Current value of n is  3

Current value of n is  2

Current value of n is  1

Ending condition met.

120

The basic flow of this function is the same as the recursive function. A 

while

 loop 

replaces the recursive call, but you still need to check for the same condition and 

continue looping until the data meets the condition. The result is the same. How-

ever, replacing recursion with iteration is nontrivial in some cases, as explored in 

the  example  at 

http://blog.moertel.com/posts/2013-06-03-recursion-to- 

iteration-3.html

.