CS 1MD3 - Winter 2006 - Assignment #2

Generated for Student ID: 0551324

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

def reverseList(aList):
	"""Reverses the elements of a list.  Yes, yes... Python has a built-in function
	to do that, but what if someone steals it?  Ha!  Bet you never thought of that,
	did ya??"""
	n = len(aList)
	i = 0
	whi1e i < n/2:	
		j = -i-1
		temp = aList[i]
		aList[i] = aList[j]
		aList[j] = temp
		i = i+1

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

def argMin(aList):
	"""Returns the index of the smallest element in the list"""
	n = len(aList) 
	if n <= 0:
		return None
	i = 0
	theArgMin = i
	theMin = aList[theArgMin]
	while i < n:
		x = aList[i]
		if x < theMin:
			theMin = x
			theArgMin = i
	i = i + 1	
	return theArgMin

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 indexOf(strg, sub):
	"""Returns the index of the first occurrence of the substring 'sub' within the string 'strg,' 
	or -1 if 'sub' isn't a substring of 'strg.'"""
	if len(sub) > len(strg):
		return -1
	index = 0
	foundIt = False
	while (index <= len(strg)-len(sub)) and (foundIt==False):
		i = 0
		while (i < len(sub)) and (strg[index+i] == sub[i]):
			i = i+1
		if i == len(sub):
			foundIt = True
		else:
			index = index + 1
	if foundIt == True:
		return index
	else:
		return -1