Pracs 4(A) and 4(B), CSE2304, CSSE, Monash, Semester 1, 2004

The [on-line] versions of the prac's may include [links], corrections and supplementary material and are to be taken as the reference documents. Check the on-line material regularly.

Candidate: You must prepare your solution to this programming exercise in advance (a 6pt subject => 12-hours work per week, every week). The designated platform, on which your solution must be demonstrated and on which it will be marked, is the `gcc' compiler running on `Linux'. If you develop a solution on another platform, it is your responsibility to ensure that it works correctly on the designated platform. Read the information under the [prac' guide], [on C and code modularity], [missed pracs] and [plagiarism] links on the [home page]. It is better to have a program that does only part of the prac' but compiles and runs rather than to have a more complex program that crashes or, even worse, does not compile. So keep copies of old working partial solutions.

Prac's are marked on the performance of your program and also on your understanding of the program. I.e. Perfect program with zero understanding => zero marks! ``Forgetting'' is not an acceptable explanation for lack of understanding. Unless otherwise noted, you must write all the code yourself, and may not use any external library routines, the usual I/O (e.g. printf) and mathematical (e.g. log) routines excepted.

NB. Remember that, from prac1, each week's prac' groups are set their own specific problems. Make sure that you do the correct problem for your prac'! You will get zero marks if you solve the wrong problem. The exam, and the prac' work, are both hurdles (half-marks) for the subject. If you fail one, or the other, or both, the highest mark that you can get for the subject is 44%(N).

Demonstrators are not obliged to mark programs that do not compile or that crash. Time allowing, they will try to help in tracking down errors, but they are not required to mark programs in such a state, particularly those that do not compile. Therefore keep backup copies of working partial-solutions (also see above).

Objectives: Graphs, reading several files. You need your solution to prac3.
(Note that, here, |x| is the absolute value of x, e.g. |3.14| = |-3.14| = 3.14. As in prac_3, you may use the Standard C Library Function `qsort' (see man qsort) if it is useful to you; don't if it isn't!)

Prac 4(A), week 10, 10-14 May 2004

[some data]

Given two C-code files, f_i and f_j, you know [how] to compute the normalised symbol-frequencies, p_i(symbol) and p_j(symbol), for each file.

Let d_ij = SUM_s |p_i(s) - p_j(s)|,   i = 1..n,  j = 1..n, where s ranges across all kinds of symbol.

This defines a symmetric, n×n, adjacency matrix, d_ij, for a collection of C-code files, f₁, f₂, ..., f_n.

 

Write a program

prac4a f1 f2 ... fn

to compute the adjacency matrix for files f1 f2 ... fn, and print it in some simple format.

Marking

[some data] NB. Prac3: "Words that do not appear in [a file] at all are ranked [by that file] after those that do appear. If two words occur equally often (even zero times), break the tie (i) by ranking a shorter word first and, for words of equal length, (ii) alphabetically."

Prac 4(B), week 11, 17-21 May 2004

Given two text files, t_i and t_j, you know [how] to compute the ranks, rank_i(word) and rank_j(word), of the correctly spelled words (and of "000" (zeroes) for all misspelled words) in t_i and in t_j.

Let r_ij = (1/(v_i+1))×{{SUM_{w in ti} |rank_i(w)-rank_j(w)|} + |rank_i("000")-rank_j("000")|},   i = 1..n,  j = 1..n,   where w ranges over all distinct words in t_i, and v_i is the number of distint words (not word occurrences) in t_i.

This defines a non-symmetric, n×n, adjacency matrix, r_ij, for a collection of text files, t₁, t₂, ..., t_n.

 

Write a program

prac4b t1 t2 ... tn

to compute the adjacency matrix for files t1 t2 ... tn, and print it in some simple format.

NB. Place the dictionary (see 3B) in a fixed, hard-coded location, e.g. dictionary.

Marking