Individual Project 2

CS 1323 Section 30, Spring 1997

Individual Project 2
Shifts and Penultimates

Due Wednesday, Jan 29, 4:29pm

- late papers penalized one grade per day or part of day, beginning 4:30pm Jan29 -
Caution: It is unwise wait until after 1:00pm on the due date to print the copy of your script that you plan to turn in.
Things often go wrong that you can't anticipate.

Ground Rules

Three projects are described below, a different one for each team member. Team members listed first or fourth on their team's roster must do Project 2A; those listed second or fifth, Project 2B; third or sixth, Project 2C.
In addition to aspects of Haskell discussed in Lessons 1-6 of the Haskell text, you may, if you find it convenient, use the intrinsic "++" operator, which builds a sequence by concatenating its right-hand operand onto the end of its left-hand operand: [a, b, c, ..., x, y, z] ++ [u, v, w, ...] = [a, b, c, ..., x, y, z, u, v, w, ...] You may also use the intrinsic function "head", which delivers the first element of its argument, which must be a non-empty sequence: head[a, b, c, ...] = a You will also need to use import directives (as described in each project) to get access to software supplied for this project.
You must not use any other aspects of Haskell not discussed in Lessons 1-6 of the Haskell textbook.
Read the Code of Conduct for ground rules that apply to all projects.
Re-read the Project Style Guide to learn about new requirements for session transcripts.

What to Hand In (see also: example project solution)

Turn in a listing of the Haskell script you write for your project, following the required standards.
Turn in a session transcript in which you show that your function operates correctly on arguments chosen to demonstrate the function's capabilities.
Explain (handwritten on the transcript) what aspects of the function's behavior are illustrated by each of your choices of demonstration examples.

Project 2A

Define a function called "nextToLast" that delivers the next to last element of a sequence (assuming the sequence has at least two elements - your function needn't work if the sequence has one element or none).

Your definition of nextToLast may use the function rightCircularShift, whose properties are described in Project 2C. To test your definition of nextToLast, download the file Project2ABS, pport.lhs from Supplied Software, and put following directive at the beginning of your Haskell script:

     import Project2ABS, pport(rightCircularShift)

This will give your program access to the rightCircularShift function.

Project 2B

Define a function called "thirdFromLast" that delivers the third from last element of a sequence (assuming the sequence has at least three elements - your function needn't work if the sequence has two or fewer elements).

Your definition of thirdFromLast may use the function rightCircularShift, whose properties are described in Project 2C. To test your definition of thirdFromLast, download Project2ABS, pport.lhs and import the function rightCircularShift, as described in Project 2A.

Project 2C

Define a function called "rightCircularShift" that delivers a sequence like its argument, except that all of the elements are shifted one place toward the end of the sequence and the last element is rotated to the beginning. That is, rightCircularShift[a, b, c, ..., x, y, z] = [z, a, b, c, ..., x, y]

Your definition may use the function leftCircularShift, which rotates a sequence in the other direction: what was the second element becomes the first, what was third becomes second, etc. ... and what was first becomes last. That is,

leftCircularShift[a, b, c, ..., x, y, z] = [b, c, ..., x, y, z, a]

To test your definition of rightCircularShift, download the file Project2CSupport.lhs from Supplied Software, and put following directive at the beginning of your Haskell script:

     import Project2CSupport(leftCircularShift)

This will give your program access to the leftCircularShift function.

You may not use the definition of rightCircularShift supplied for the people doing Projects 2A and 2B. That definition uses aspects of Haskell that are off limits for this project because they are not covered in Lessons 1-6.

CS 1323 Section 30 - Fundamentals of Computer Programming - Spring 1997 Instructor: Rex Page (Email: page@ou.edu)
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