[Tutor] Calculate 4**9 without using **

[Sri Kavi]

Like I just said in my other message, I was trying to reply to Tasha
Burman, but I was in digest mode and I didn't know how to change my
subscription options in order to reply to individual messages. I also don't
know if it's an assignment, but I'm a beginner learning to program, too :)

>What if any of the following are true, and what should be done in each
case?
>   if exponent ==1: .....
>   if exponent = 0: .....
>   if exponent < 0: .....

Here's my implementation.

In Python 2.7.12

def power(base, exponent):
    if exponent == 0:
        return 1
    elif exponent > 0:
        result = base

        for _ in xrange(1, exponent):
            result *= base
        return result
    else:
        exponent = -exponent
        result = base

        for _ in xrange(1, exponent):
            result *= base
        return 1.0 / result

In Python 3.6.0

def power(base, exponent):
    if exponent == 0:
        return 1
    elif exponent > 0:
        result = base

        for _ in range(1, exponent):
            result *= base

        return result
    else:
        exponent = -exponent
        result = base

        for _ in range(1, exponent):
            result *= base
        return 1 / result

Please share your thoughts.

On Sun, Mar 5, 2017 at 7:37 AM, Alex Kleider <akleider at sonic.net> wrote:

> On 2017-03-04 08:17, Sri Kavi wrote:
>
> I'm a beginner learning to program with Python. I'm trying to explain a
>> solution in plain English. Please correct me if I'm wrong.
>>
>
> Create a function that takes base and exponent as arguments.
>>
>
> Is seems that you are facing the same problem as Tasha Burman.
> Sounds like an assignment meant to exercise your use of iteration.
> i.e. ** and various built in power functions that have been suggested are
> out of bounds.
>
> In the body of the function:
>> set a result variable to the base.
>>
>
> def pwr(base, exponent):
>     ....
>     res = base
>     ...
>
>> User a for-loop with a range of 1 to the exponent.
>>
>
>     for i in range(begin, end):  # The challenge is to pick begin and end.
>
> end will be a function of exponent but not exponent itself.
> I don't think 1 is a good choice for begin.
> Picking the correct begin is related to dealing with the following:
>
> What if any of the following are true, and what should be done in each
> case?
>     if exponent ==1: .....
>     if exponent = 0: .....
>     if exponent < 0: .....
> Each of the first two might deserve its own return statement.
>
>
>> With each iteration, set the result to the product of result times base.
>>
>
>     res *= base  # same as res = res * base
>
>
> It's a fun little exercise- a bit more complex than I initially thought it
> would be.
>
> Please share your implementation.
>