Computer Science Fundamentals (CS153 2004S)

Lab: Searching

Summary: In this laboratory, we explore different issues related to searching.

Contents:

Exercises

Exercise 0: Preparation

a. Start DrScheme.

b. Make sure that you understand the purpose of get-key in binary-search from the reading on searching.

c. Add the procedures from that reading to your library of utilities.

d. Create a vector, names, of a dozen or so lists, each of which contains a last name and a first name. Order the list by last name.

Exercise 1: Testing Our Procedures

a. Using sequential-search-list, search for the letter #\a in various lists of characters.

Note that it's probably easiest to create a list of characters with string->list.

b. Using sequential-search-vector, search for the letter #\a in various vectors of characters.

c. Develop some tests for search-list-for-keyed-value. For example, you might create a list of cartoon characters and their sidekicks and search the list for character or sidekick.

Exercise 2: Extending sequential-search-vector

Write a procedure that takes a predicate and vector as parameters and, using sequential-search-vector as a helper, finds a value in the vector that matches the predicate or returns #f if no such value exists. (Like sequential-search-vector, this procedure searches vectors; unlike sequential-search-vector and like sequential-search-list, this procedure returns a matching value, rather than an index.

Exercise 3: Observing Binary Search

Add calls to display and newline to the definition of binary-search, so that it prints out the values of lower-bound and upper-bound each time the kernel procedure is called. How many recursive calls are made as binary search finds your name in the list names? How many are made in an unsuccessful search?

 

History

 

Disclaimer: I usually create these pages on the fly, which means that I rarely proofread them and they may contain bad grammar and incorrect details. It also means that I tend to update them regularly (see the history for more details). Feel free to contact me with any suggestions for changes.

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Samuel A. Rebelsky, rebelsky@grinnell.edu