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Hey all, beginner here. (Background:I have a BS in Chemical Engineering and an MS in Industrial Engineering but have always wanted to learn Python!!)

I was trying a program to find the value of pi. I wrote a code for it and it works well, except it crashes at n > 994.

I used recursion here.

Can anyone let me know why it crashes after n=994 :/

Here’s my code.

#Program that prints the approximate value of pi
#4/1 - 4/3 + 4/5 - 4/7 + 4/9 - 4/11...
#nth term of the sequence is: \n", (4/(2*n-1)*(-1)**(1-n))) using simple math.
#Code begins

import math
def T(n):
    Tn =(4/(2*n-1)*(-1)**(1-n)) #using some simple math for arithmetic progressions
    if n==0:
        return 0
    if n==1:
        return 4
    else:
        return Tn+T(n-1)
n=eval(input("Enter the value of n: \n"))
print ("The approximate value of pi is:", T(n))
print ("The difference from the actual value of pi is:", T(n)-math.pi) “

#Code ends

Python has a recursion limit to prevent stack overflows. You're probably hitting the limit.

Just tried this locally with Python 3.4 (64 bit). No problem using n = 100, 200 or 500. It fails with a recursion depth error with n =1000.