COMP9044 Week 09 Laboratory Exercises Solution

Before the lab you should re-read the relevant lecture slides and their accompanying examples.


Create a new directory for this lab called lab09, change to this directory, and fetch the provided code for this week by running these commands:
$ mkdir lab09
$ cd lab09
$ 2041 fetch lab09
Or, if you're not working on CSE, you can download the provided code as a zip file or a tar file.


While in general automatically extract all dependencies for complex software systems, a tool that generate most of a Makefile can be very useful.
Your task in this exercise is to write a Perl script makemake.pl which generates an appropriate Makefile for a multi-file C program.
This will require making a number of assumptions.
Your task
Write a Perl script makemake.pl to generate a Makefile that will build the C program whose source code is in the current directory.
The script takes no arguments, and writes the Makefile text to its standard output.
Assumptions
The current directory contains all code files from only one C program.
The C program is composed only of .c and .h files.
Exactly one .c file will contain a main() function.
The main() function appears on a line that matches the regexp
/^s*(int|void)s*mains*(/
No other line in the files matches this regex.
The executable is named after the file containing the main() function (without the .c)
Any line starting with #include is a genuine include line
(ignore multi-line comments and other preprocessor commands like #if)
All the dependencies that need to be included in the Makefile involve files that exist in the current directory
Example Output
Three example C programs are available as a zip file
Here is the output your program should produce for each of these examples:

$ unzip /web/cs2041/20T2/activities/makemake/examples.zip Archive: examples.zip creating: easy/ extracting: easy/graphics.h inflating: easy/graphics.c ....
$ cd easy $ ls easymain.c graphics.c graphics.h world.c world.h
$ ../makemake.pl >Makefile
$ cat Makefile
CC = gcc
CFLAGS = -Wall -g
easymain: easymain.o graphics.o world.o
$(CC) $(CFLAGS) -o $@ easymain.o graphics.o world.o
graphics.o: graphics.h world.h graphics.c easymain.o: world.h graphics.h easymain.c world.o: world.h world.c
$ make gcc -Wall -g -c -o easymain.o easymain.c gcc -Wall -g -c -o graphics.o graphics.c gcc -Wall -g -c -o world.o world.c gcc -o easymain easymain.o graphics.o world.o
$ cd ../medium
$ ls
a.c a.h aaa.c aaa.h b.c b.h bb.c bb.h c.c c.h common.h main.c
$ ../makemake.pl >Makefile
$ cat Makefile
CC = gcc
CFLAGS = -Wall -g
main: a.o aaa.o b.o bb.o c.o main.o
$(CC) $(CFLAGS) -o $@ a.o aaa.o b.o bb.o c.o main.o
b.o: b.h bb.h aaa.h b.c
c.o: c.h c.c
a.o: common.h a.h a.c bb.o: bb.h aaa.h bb.c main.o: a.h c.h b.h bb.h aaa.h main.c
$ make gcc -Wall -g -c -o a.o a.c gcc -Wall -g -c -o aaa.o aaa.c gcc -Wall -g -c -o b.o b.c gcc -Wall -g -c -o bb.o bb.c gcc -Wall -g -c -o c.o c.c gcc -Wall -g -c -o main.o main.c gcc -o main a.o aaa.o b.o bb.o c.o main.o
$ cd ../hard
$ ls circ1.c circ1.h circ2.c circ2.h circmain.c
$ ../makemake.pl >Makefile
$ cat Makefile
CC = gcc
CFLAGS = -Wall -g
circmain: circ1.o circ2.o circmain.o
$(CC) $(CFLAGS) -o $@ circ1.o circ2.o circmain.o
circ1.o: circ1.h circ2.h circ1.c circmain.o: circ1.h circ2.h circmain.c circ2.o: circ2.h circ1.h circ2.c
$ make gcc -Wall -g -c -o circ1.o circ1.c
gcc -Wall -g -c -o circ2.o circ2.c gcc -Wall -g -c -o circmain.o circmain.c gcc -o circmain circ1.o circ2.o circmain.o
Further Requirements
You should include four standard lines at the front of every Makefile
# Makefile generated at timestamp in format given above
CC = gcc
CFLAGS = -Wall -g
There should be a blank line immediately before each Make rule
Hints
You could use a hash to represent all dependencies
The Perl builtin glob is an easy way to get a list of the .c or .h files in the current directory
You do not need to produce rules for dependencies on standard .h files (e.g. stdio.h) You can assumes includes of standard libraries use <...> notation, e.g:
#include $lt;stdio.h>
When you think your program is working, you can use autotest to run some simple automated tests:
$ 2041 autotest makemake
When you are finished working on this exercise, you must submit your work by running give:
$ give cs2041 lab09_makemake makemake.pl


Write a Perl regex which matches unary number iff it is composite (not prime).
In other words write a regex that matches a string of n ones iff n is composite.
A test program is provide to assist you in doing this:

Download test_regex_prime.pl, or copy it to your CSE account using the following command:
$ cp -n /web/cs2041/20T2/activities/regex_prime/test_regex_prime.pl .
For example to test the regex ^1(11)+1$ against the integers 2 to 12, you can run
$ chmod 755 test_regex_prime.pl
$ test_regex_prime.pl 2 12 '^1(11)+1$'
2 = 11 unary - prime 3 = 111 unary - prime
4 = 1111 unary - composite
5 = 11111 unary - prime
6 = 111111 unary - composite
7 = 1111111 unary - prime
8 = 11111111 unary - composite
9 = 111111111 unary - prime
10 = 1111111111 unary - composite
11 = 11111111111 unary - prime
12 = 111111111111 unary - composite
Put your solution in regex_prime.txt, for example:
$ test_regex_prime.pl 40 50 "$(cat regex_prime.txt)"
40 = 1111111111111111111111111111111111111111 unary - composite
41 = 11111111111111111111111111111111111111111 unary - prime
42 = 111111111111111111111111111111111111111111 unary - composite
43 = 1111111111111111111111111111111111111111111 unary - prime
44 = 11111111111111111111111111111111111111111111 unary - composite
45 = 111111111111111111111111111111111111111111111 unary - composite
46 = 1111111111111111111111111111111111111111111111 unary - composite
47 = 11111111111111111111111111111111111111111111111 unary - prime
48 = 111111111111111111111111111111111111111111111111 unary - composite
49 = 1111111111111111111111111111111111111111111111111 unary - composite
50 = 11111111111111111111111111111111111111111111111111 unary - composite
Your regex must be less than 80 characters.
Hint: you can't do this with a true regular expression, i.e using |*() alone, you need to use features that Perl adds.
Don't google for other people solutions - see if you can come up with your own.
When you think your program is working, you can use autotest to run some simple automated tests:
$ 2041 autotest regex_prime
When you are finished working on this exercise, you must submit your work by running give:
$ give cs2041 lab09_regex_prime regex_prime.txt


When you are finished each exercises make sure you submit your work by running give.
You can run give multiple times. Only your last submission will be marked.
Don't submit any exercises you haven't attempted.
You check the files you have submitted here.
After automarking is run by the lecturer you can view your results here. The resulting mark will also be available via give's web interface.
Lab Marks
When all components of a lab are automarked you should be able to view the the marks via give's web interface or by running this command on a CSE machine:
$ 2041 classrun -sturec

For all enquiries, please email the class account at cs2041@cse.unsw.edu.au
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