Adding exercise-2.1.py

AllenDowney · AllenDowney · commit 20d7a16060b3 · 2013-08-28T09:57:28.000-04:00
diff --git a/exercise-2.1.py b/exercise-2.1.py
@@ -0,0 +1,52 @@
+"""
+Code example from Think Python, by Allen B. Downey.
+Available from http://thinkpython.com
+
+Copyright 2013 Allen B. Downey.
+Distributed under the GNU General Public License at gnu.org/licenses/gpl.html.
+
+
+If you type an integer with a leading zero, you might get
+a confusing error:
+
+>>> zipcode = 02492
+                  ^
+SyntaxError: invalid token
+
+Other numbers seem to work, but the results are bizarre:
+
+>>> zipcode = 02132
+>>> zipcode
+1114
+
+Can you figure out what is going on?  Hint: display the
+values 01, 010, 0100 and 01000.
+
+"""
+
+print 01, 010, 0100, 01000
+
+
+"""
+
+The result is
+
+1 8 64 512
+
+which you might recognize as powers of 8.
+
+If a number begins with 0, Python treats it as an octal number,
+which means it is in base 8.
+
+So in the example, 02132 is considered
+
+"""
+
+print 2 * 512 + 1 * 64 + 3 * 8 + 2
+
+"""
+
+which is 1114.
+
+"""
+
