CSC207.01 2014S, Class 43: Hash Tables, Continued ================================================= _Overview_ * Preliminaries. * Admin. * Questions on the project. * Questions on hash tables. * Lab. Preliminaries ------------- ### Upcoming Work * Reading for Friday: You may review the reading on Hash Tables. (You need not.) * Today's writeup: Exercise 3b. * Part 1 of the project is due tonight. * I'll take questions after the introductory stuff. ### Admin * Yesterday's MathLAN problem solved - The lock daemon was broken. * The longstanding MathLAN problem has not been solved. ### Extra Credit * Convo today: Philip Deloria, Professor of History and Native American Studies, University of Michigan. * CS extra Thursday: Charlie Eddy on Kinect. * CS Pub Night Thursday. * CS table Friday: Big Data (Stone leads). * Get and wear one of the 1 in 4 shirts. * Any other sexual assault awareness week activity. * Iowater project April 19 - Tag drains. Mail iowater@grinnell.edu for details. * ### Questions on the Project _Do we have to support top-level arrays and not just top-level objects?_ > Yes. _When we are handling numbers, how do we deal with the various kinds?_ > Option 1: Always use BigDecimal. > Option 2: Pay attention to what symbols you've seen in the number (or build the string and search for symbols). If it includes a decimal point, it's a decimal number. If not, it's an integer. _Where would you make that decision?_ > Probably in the parser. _What advice does E-guy have?_ > Use a wrapper class. But Sam says it's up to you. _What's the performance of charAt and substring?_ > charAt is O(1) > I don't know the implementation of substring. I think it is O(length of resulting string), but it could be O(1) _What's the performance of "build a string by appending characters"?_ > O(n^2), unless you are using a StringBuffer/StringBuilder. > But you probably want to use substring instead. _Do key/value pairs appear anywhere besides in objects?_ > No. Questions --------- Lab --- * * Today's writeup: Exercise 3b.