[Tutor] learning recursion

[Denis Heidtmann]

Running python 2.7 on Ubuntu 12.04

Code:
def fib2(n):
if n==1:
return 1
elif n==2:
return 1
else:
return fib2(n-2) +fib2(n-1)

The above works:

>>> fib2(7)
13
>>> fib2(4)
3

>>> for i in range(4):
...     print fib2(i)
...

The above results in an error:

Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "testing.py", line 21, in fib2
    return fib2(n-2) +fib2(n-1)
  File "testing.py", line 21, in fib2
    return fib2(n-2) +fib2(n-1)

<snip>

 File "testing.py", line 21, in fib2
    return fib2(n-2) +fib2(n-1)
RuntimeError: maximum recursion depth exceeded
>>>

Is this some subtle problem or is it some stupid mistake on my part?

Thanks for your help.

-Denis H.
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