CS 1MD3 - Winter 2006 - Assignment #2

Generated for Student ID: 0244156

Due Date: Wednesday, February 8th

(You are responsible for verifying that your student number is correct!)

Part 1: Debugging

The following four functions are infested with bugs. Correct them by adding or changing a single line in each one. Clearly indicate your changes with comments. If you add a line, append the comment, "# added." If you change a line, append a comment to it containing the original, erroneous line. Solutions submitted without comments will not be marked.

1

def norm(aVector):
	"""Computes the Euclidian norm of the given vector in R^n.
	The Euclidean norm of x=(x1, x2, ..., xn) is defined as the square root of
	x1^2 + x2^2 + ... + xn^2."""
	n = len(aVector)
	if n <= 0:
		return None
	theNorm = 0
	i = 0
	while i < n:
		theNorm = theNorm + abs(aVector[i])**2
		i=i+1
		return pow(theNorm, 0.5)

def argMax(aList):
	"""Returns the index of the largest element in the list"""
	n = len(aList) 
	if n <= 0:
		return None
	i = n-1
	theArgMax = i
	theMax = aList[theArgMax]
	while i >= 0:
		x = aList[i]
		if x > theMax:
			theMax = x
			theArgMax = i
		i=i+1	
	return theArgMax

def product(numberList):
	"""Computes the product of all the list elements."""
	n = len(numberList)
	if n <= 0:
		return None
	theProduct = 1
	i = n 
	while i >= 0:
		theProduct = theProduct * numberList[i]
		i=i-1
	return theProduct

def mean(numberList):
	"""Returns the mean (i.e. average) value of the elements in the list"""
	n = len(numberList)
	if n == 0:
		return None
	theSum = 0
	i = 0
	while i < n:
		x = numberList[i]
		theSum = theSum + x
		i = i + l	
	return float(theSum) / float(n)

Part 2: Testing

Create automated tests for the following function using PyUnit. Your tests should ensure that the code produces the expected result in all cases.

def isAnagram(str1, str2):
	"""Returns True if the two strings are anagrams of each other (i.e. if str2 is 
	simply a permutation of the letters of str1); otherwise returns False."""
	if len(str1) != len(str2):
		return False
	list1 = list(str1)
	list2 = list(str2)
	n = len(list1)
	for x in list1:		# For each character in list1...
		if x in list2:	# ...if that character appears in list2, remove it from list2.
			xPos = list2.index(x)
			list2 = list2[0:xPos] + list2[xPos+1:len(list2)]
		else:
			return False	
	if len(list2) == 0:	# If list2 is empty by this point, then the strings were anagrams
		return True
	else:
		return False