Lecture Wed Week 7

1. Lecture Wed Week 7 • Midterm grades on gradesource • Graded out of 26 (free point) • Question 1 confusing – everyone gets full points • Solutions posted soon • Great job!

2. Could you help me out Please be completely honest…

3. How many hours did you study for the midterm? • None • 1 hour • 2 hours • 3 hours • More than 3 hours

4. How did you spend your study time? • Working with the sample midterm/clicker questions • Reading the book • Both fairly evenly

5. Were you surprised by the content of the exam? • Not at all • A little bit • Quite a bit • I was completely surprised

6. Tech and Society #2:Ifs and Events on the Web…(due Tuesday Week 8) • Let’s look on moodle • The Web: • New Opportunities for Social Particpation • Explore account creation and a web site • Answer “questions” (like lab) on surveymonkey about the experience • Forum Post • Reflection on power of “pervasive” computing

7. Suppose there is a list of Customers (people waiting in line). You want to serve each customer one at a time, so each one should walk into the store one at a time. • Use a DoTogether tile • Use a DoInOrder tile • Use a ForAllTogether tile • Use a ForAllInOrder tile

8. Which of the following types can be used in a list? • Rockette • Rockette’s Thighs • Rockette’s Hips • All of the Above

9. If I declare a list thusly, and use a ForAllInOrder tile, what order do the rockettes kick?

10. Finish Section 7.2 While (Indeterminate) Loops • Did you watch the video? • Please do!

11. Chapter 9-1 Lists • Our last Alice chapter  • After Chapter 9, we’ll move into the white and red Excel book • A certain amount of background excel knowledge is expected. • We have an online quiz to help you figure out if you don’t have that background • And an online tutorial to help you get it • You will need to do this on your own

12. Old Budweiser Commercial • Three frogs, together they say Budwesier • Frog 1 (on left) “Bud” • Frog 2 (in middle) “weis” • Frog 3 (on right) “er” • That’s hard – let’s start with • Three frogs talk in order left to right • Like this:

13. What does this code do?

14. What does this code do? • The frogs talk in order left to right • The frogs talk in backwards order (right to left) • Each frog talks, but the order depends

15. It ALWAYS goes in the order you make your list in

16. Let’s assume I remake my list like this (L to R):

17. What if I want the frogs to say Hello (left to right) 5 times? • Make a counted loop run five times INSIDE (as the inner loop) the ForAllInOrder loop • Make a counted loop run five times with the ForAllInOrder loop INSIDE (as the inner loop)

18. Predict: What would this code do? • ???

19. By the way… you can make a list out of different kinds of objects • Do the wave with different “People” objects • Make different types of flowers grow And out of other things…

20. Problem: Each frog should say something different… Bud Wei Ser

21. What programming construct would you use? • An if statement inside the For all in order • A counted loop inside the For all in order • An if statement before the For all in order • A counted loop outside the For all in order • I don’ t know…

22. There are (at least) two possible solutions… What is the BEST explanation of why is one better than the other? • Option 1 is better because it is shorter • Option 1 is better because it does the least number of “checks” (or boolean condition evaluations) • Option 2 is better because it makes clear exactly what the “checks” (or boolean condition evaluations) are • Option 2 is better because it has a regular structure with empty “else” portions

23. Shorter • Least Boolean Checks C) Clear BooleanChecks D) RegularStructure with Empty “else”es

24. Remember this… • “Good” programs aren’t (always) the ones that • Make it easiest on the programmer • Are easiest for humans to read • Require least amount of effort from programmer • Instead they are (usually) the ones that • Require least computing work (by computer) • Are easiest to adapt to new situations • Methods and parameters come in here

25. There’s an EVEN BETTER way to write this program! • Think about this… • What if we had… • A list of froggies • Some number of frogs that want to talk • A list of words • Exactly the same “number” of Strings to be “said” by each of those frogs… • How can we make a program that will make each frog say a specific word • In ONLY 2 LINES OF CODE?!?!?

26. Let’s make the beetles do a more complicated dance… • Like this:

27. Which structure would you want? • One ForAllInOrder loop • One ForAllInOrder loop with an if statement inside • One if statement with a ForAllTogether inside • None of the above

28. Does this code correctly implement our intended behavior? • Yes • No • I don’t know And WHY!

29. What is new about this code? • Nested “for all” loops • A loop that “iterates” over all items in a list • Inside that is another loop that goes over all the items in a list • In this case, happen to be the same list • Wow, you can do complicated things now… 

31. There are 4 beetles, how many times is this instruction executed? • 4 • 12 • 16 • 48 • I don’t know

32. Parameters to methods:We can do better now!

33. How would we do our “new” solo (with backup)