Fibonacci sequence
==================


Example code
------------

.. interactive_code_block:: 
   :caption: Straightforward version without trickery

   length = 15
   a = 0
   b = 1
   for i in range(length):
       print(a, end=' ')
       c = a + b
       a = b
       b = c


.. interactive_code_block:: 
   :caption: Straightforward, compacter version with some trickery

   length = 15
   a, b = 0, 1  # Creating and unpacking a tuple in a single line
   for i in range(length):
       print(a, end=' ')
       a, b = b, a+ b


Exercise 1
----------

Complete the code by replacing ``# ..........``.

.. interactive_code_block:: 
   :caption: Create a function that prints the sequence

   def fibonacci(length):
       # ..........
       # ..........
       # ..........

   fibonacci(15)


..
    def fibonacci(length):
    a, b = 0, 1
    for i in range(length):
        print(a, end=' ')
        a, b = b, a+ b

    fibonacci(15)


Exercise 2
----------

Complete the code by replacing ``# ..........``.

.. interactive_code_block:: 
   :caption: Create a function that returns the sequence

   def fibonacci(length):
       # ..........
       # ..........
       # ..........

   result = fibonacci(15)
   print(result)

..
    def fibonacci(length):
        result = []
        a, b = 0, 1
        for i in range(length):
            result.append(a)
            a, b = b, a+ b
        return result

    result = fibonacci(15)
    print(result)