bpo-31757: Make Fibonacci examples consistent (#3991)

1 files changed, 10 insertions, 8 deletions

diff --git a/Doc/tutorial/introduction.rst b/Doc/tutorial/introduction.rst
index 8956aa5..2fa894a 100644
--- a/Doc/tutorial/introduction.rst
+++ b/Doc/tutorial/introduction.rst
@@ -458,16 +458,18 @@ First Steps Towards Programming
 ===============================
 
 Of course, we can use Python for more complicated tasks than adding two and two
-together.  For instance, we can write an initial sub-sequence of the *Fibonacci*
-series as follows::
+together.  For instance, we can write an initial sub-sequence of the
+`Fibonacci series <https://en.wikipedia.org/wiki/Fibonacci_number>`_
+as follows::
 
    >>> # Fibonacci series:
    ... # the sum of two elements defines the next
    ... a, b = 0, 1
-   >>> while b < 10:
-   ...     print(b)
+   >>> while a < 10:
+   ...     print(a)
    ...     a, b = b, a+b
    ...
+   0
    1
    1
    2
@@ -483,7 +485,7 @@ This example introduces several new features.
   first before any of the assignments take place.  The right-hand side expressions
   are evaluated  from the left to the right.
 
-* The :keyword:`while` loop executes as long as the condition (here: ``b < 10``)
+* The :keyword:`while` loop executes as long as the condition (here: ``a < 10``)
   remains true.  In Python, like in C, any non-zero integer value is true; zero is
   false.  The condition may also be a string or list value, in fact any sequence;
   anything with a non-zero length is true, empty sequences are false.  The test
@@ -516,11 +518,11 @@ This example introduces several new features.
   or end the output with a different string::
 
      >>> a, b = 0, 1
-     >>> while b < 1000:
-     ...     print(b, end=',')
+     >>> while a < 1000:
+     ...     print(a, end=',')
      ...     a, b = b, a+b
      ...
-     1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,
+     0,1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,
 
 
 .. rubric:: Footnotes