Answer to Question #241499 in Python for Joel

Question

List and describe three possibilities to consider if a function is not working ?

Create examples of each possibility and list the code for each example ?

Define " precondition " and " precondition " ?

Answer 1

Possibilities are:

When precondition is violated.

When postcondition is violated

When there is wrong usage of return value or the return value is not placed correctly.

Code example to illustrate the above possibilities

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

Precondition -A problem before the function’s parameters are passed into the parameters.