Summary: In this assignment, you will sketch or implement a version of the standard binary search algorithm.
Assigned: Monday, 20 January 2003.
Due: noon, Tuesday, 21 January 2003.
Citation: Much of the problem statement is based on Column 4 of the second edition Jon Bentley's Programming Pearls.
Bentley, Jon (2000). Programming Pearls, 2nd Edition. Reading, MA: Addison-Wesley.
Collaboration: You may certainly discuss the assignment with other students. However, each student should turn in his or her own solution. Once you've started to write code, you may not show your code to others.
Reuse: Please do not reuse code you've written previously
or that you've found on the Web. The goal of this assignment is to see how
you do implementing binary search
Submitting Your Work: Submit your source code with the ECA. If you can't get it to work, email me your source code.
Implement (in Scheme, Java, or Pseudocode) the following version of
Binary search. If you implement in pseudocode, you should be confident
that your algorithm would work if you translated it into a real
programming language. If you use Scheme, substitute
array in the problem statement.
n, an integer
x, a sorted array of integers indexed from 0 to n-1
t, an integer
|Purpose||Determine if t appears in x.|
|Produces||p, an integer|
|Preconditions||x is sorted in increasing order. That is,
x[i] <= x[i+1] for all reasonable
n >= 0.
|Postconditions||If t appears in x, x[p] = t.
If t does not appear in x, p = -1.
|Process||Keep track of the range within the array that holds t (if t is anywhere in the array). Initially, the range is the entire array. The range is shrunk by comparing its middle element to t and discarding half the range. The process continues until t is found or until the range in which it must lie is known to be empty. (Bentley 2000, p. 34)|
Tuesday, 14 January 2003 [Samuel A. Rebelsky]
Monday, 20 January 2003 [Samuel A. Rebelsky]
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.
This document was generated by
Siteweaver on Fri May 2 14:19:32 2003.
The source to the document was last modified on Mon Jan 20 13:16:55 2003.
This document may be found at