There is a bad mistake in the Question 6 of the exam!

The example shown in incorrect. The result should be:

> (define p (mlist 1 2 3 4 5))
> (make-cumulative! p)
> p
{1 3 6 10 15}

The value of each element in the result should be the sum of all elements in the original list up to and including that element. So, the first element in the output list is 1 = 1, the second is 1 + 2 = 3, the third is 1 + 2 + 3 = 6, the fourth is 1 + 2 + 3 + 4 = 10, and the fifth is 1 + 2 + 3 + 4 + 5 = 15.

Sorry for the confusion on this. You will receive full credit for this question if your answer either solves the problem as corrected here, or produces the same outputs as the example shown in the original exam.

Special thanks to Caroline Mattey for reporting the problem.

Class 38: Slides [PPTX], Notes [PDF]

J.C.R. Licklider and Robert W. Taylor, The Computer as a Communication Device, 1968.

Tim Berners-Lee: Answers for Young People

Sorry, I will not be able to hold my scheduled office hours today. I will have my office hours tomorrow (Tuesday, 11-noon). If that doesn’t work, please email me to arrange another time. (Kristina will still have her normal office hours in Davis Commons, noon-1:30 today.)

Everyone in the class should have received an email from the alonzo-bot that summarizes the grades recorded for you so far. If you did not receive this email, or found anything incorrect or confusing in it, please email me,

If you did the J option for PS8, this email should also contain comments on PS8. If you did the other option for PS8, you should have received an email from me in reply to your message.

Comments for previous problem sets are now available: Problem Set 6 Comments, Problem Set 7 Comments, and Problem Set 8[J] (Part 1) Comments. Sorry for not posting the PS6 and PS7 comments earlier.

The second part of PS8 for the Java option is here: Problem Set 8J (Part 2): Typed Aazda.