EECS 110: Homework I

1
EECS 110 Homework I

• Spring 2010

2
Homework I

• Problems
• Rock-Paper-Scissors (fair game)
• Functions Frenzy
• Extra Problems
• Pig Latin
• Scoring Paper

3
Problem 3 Rock, Paper, ScissorsOverview

• Objective Play rock-paper-scissors fairly
• Steps for the program
• Choose the computer choice randomly(without
  revealing this value to the user)
• Ask the user for their choice(give warning for
  incorrect choice)
• Figure out the winner print out the result

4
Problem 3 Rock, Paper, ScissorsRandom choice

• Using choice function from random package
• Example code from random import s
  choice('thread','yarn','twine') print 'I
  chose', s

5
Problem 3 Rock, Paper, ScissorsA while loop

• Execute a block of code repeatedly as long as a
  condition is satisfied.
• Application Keep asking as long as incorrect
  choice is given by the user
• Example code answer 'no' while answer
  'no' body of the program answer
  raw_input('Want to stop? ')

6
Problem 4 Recursive FunctionsOverview

• Problems
• Multiplication mult(n,m)
• Dot product dot(L,K)
• First index ind(e,L)
• Scoring Letter letterScore(let)
• Scoring Word scrabbleScore(S)
• Recursive Functions
• Base case
• Recursive part

7
Problem 4 Recursive FunctionsMultiplication

• Return product of 2 integers
• Requirements
• Use recursion
• Use only addition, subtraction, negation
• Hints
• Use the construction of function power as a guide
• m n m added together n times
• Handling negative numbers

8
Problem 4 Recursive FunctionsDot Product

• Return dot product of any 2 lists
• Return 0.0 when
• Lists have unequal lengths
• Empty lists
• Hints
• Use the construction of function mysum as a guide
• Dot product sum of products of elements in the
  same position
• Example 5,3 o 6,4 56 34 42

9
Problem 4 Recursive FunctionsFirst Index

• Return first index of an element in a list
• Requirements
• Use Recursion
• Counting starts at 0
• Nonexistence return any integer len(L)
• Examples gtgtgt ind(42, 55,77,42,12,42,100)? 2
  gtgtgt ind('i', 'team')? 4

10
Problem 4 Recursive FunctionsScoring Letter

• Return score of a letter based on
• Requirements
• No recursion needed
• Return 0 for input that is not from 'a' to 'z'
• Hints
• Use in keywordgtgtgt 'a' in 'this is a string with
  letter a'True

11
Problem 4 Recursive FunctionsScoring Word

• Return score of a string
• Requirements
• Use recursion
• Hints
• Use the construction of function mylen as a guide
• Use letterScore(let) as previously defined

12
Extra Credit 1 Pig LatinOverview

• The warm-up pigLatin(s)
• The challenge spamLatin(s)

13
Extra Credit 1 Pig LatinThe Warm-up pigLatin(s)

• Input single word, lower letter string s
• Translate to Pig Latin based on these rules
• If s is an empty string
• return an empty string
• If s begins with a vowel (a,e,i,o,u)
• Append 'way' to the end of s
• Example pigLatin('one') returns 'oneway'
• If s begins with a consonant (the rest including
  y)
• Move this consonant to the end
• Then append 'ay' to the end
• Example pigLatin('be') returns 'ebay'

14
Extra Credit 1 Pig LatinThe Challenge
spamLatin(s)

• Input single word, lower letter string s
• Translate to Pig Latin based on these rules
• If s is an empty string, or begins with a vowel,
  same with pigLatin(s)
• If s begins with a consonant
• Move all initial consonants to the end
• Then append 'ay' to the end
• Example pigLatin('string') returns 'ingstray'

15
Extra Credit 1 Pig LatinThe Challenge
spamLatin(s)

• Rules (continue)
• If s starts with 'y' which is followed by
• a vowel, then consider this 'y' to be a consonant
• a consonant, then consider this 'y' to be a vowel
• spamLatin('yttrium') returns 'yttriumway'
• spamLatin('yoohoo') returns 'oohooyay
• Other cases free to decide

16
Extra Credit 2 Scoring FileOverview

• Input a file name
• Output
• Total Scrabble score
• Total number of alphabetic characters
• Average Scrabble-score-per-letter
• Important both upper- and lower-case letters

17
Extra Credit 2 Scoring FileReading a File

• def printFileToScreen(fileName) f
  file(fileName) text f.read() f.close()
• print 'The file contains' print print text

18
Extra Credit 2 Scoring FileLarge Recursive Call

• Recursive stack is limited at 1000 calls by
  default
• Change this temporarilyimport
  syssys.setrecursionlimit(100000)?

19
Extra Credit 2 Scoring FileTesting

• Test on 2 additional files
• Convert your files to plain text first
• Include the results at the top of your program

20
Last points

• Name your files correctly
• Include docstring for your functions
• Test thoroughly
• Good luck