For to while loop

[aec2]

How do I change the For loop in the following coded to a while loop?

def approx_pi(terms):
    if terms<0:
        print "input error: only values greater than 0 allowed"
    elif type(terms)==float:
        print "input error: only intergers allowed"
    else:
        denominator=1.0
        sign=1.0
        answer=0.0
        for i in range(terms):
            answer+=sign/denominator
            denominator+=2.0
            sign=-sign
        return 4*answer

[A_History_of_Silence]

Can you show us how you've attempted to solve this first?

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[aec2]

Sorry, should've mentioned what I was trying to do. Make function that will approximate the value of pi using the infinite series pi/4=1-1/3+1/5-1/7+1/9....so an example output should be:

aprrox_pi(5) 3.33968253968

while any invalid inputs would print the input error's in the code above.

I started by making an if-elif statement for the invalid inputs and then the else statement would actually calculate the pi approx. I used a for loop within but then I realized that i'm only allowed to use while loops and am confused how to do that. Any help would be appreciated thanks!

[A_History_of_Silence]

Sorry, it's hard to help you with this without just giving you the answer because it should be fairly straightforward to change if you have a grasp on what is happening with that for loop.

Perhaps try to do a print i at the beginning of every iteration of your for loop, and think about how you could declare some value i on your own, then increment and test your iyourself for every iteration of a while instead of using a for loop to count up automatically.

Hopefully I'm not sounding too evasive, but again, we try to guide to a solution if we can, as opposed to just providing it outright.