COSC 235B David A. Sykes
1
Test #2
April 11, 2008
Name: ___________________________ Pledged: ___________________________
Answer all questions. If you can’t remember Python syntax to do something, put in a comment about
what you would like to do.
1. Label three of the truth tables below with the Boolean operators and, or, and not. Label the truth
table that does not match one of these three operators with unknown.
____________ ____________ ____________ ___________
A B A op B
False False False
False True True
True False True
True True True
A op B
False True
False True
True False
True False
A B A op B
False False True
False True True
True False True
True True False
A B A op B
False False False
False True False
True False False
True True True
2. The code for the function findIndexOf() relies on the short-circuit evaluation of Boolean expressions
a. Circle the expression that uses short-circuit evaluation.
b. Explain how the code would fail if short-circuit evaluation was not used.
def findIndexOf(aList, value):
"""Return the lowest index k such that aList[k] equals value if
such a k exists. Return len(aList) otherwise."""
# Look through the list for value, starting at index 0
k = 0
while k < len(aList) and aList[k] != value:
k += 1
# At this point, either k == len(aList) or aList[k] == value
return k
