CSCI 2500 — Computer Organization Lab 03


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CSCI 2500 — Computer Organization
Lab 03 (document version 1.0)
Checkpoint 1: Download the lab03-data.dat file and attempt to decipher what the file
contains. From the shell, try viewing the file in a text editor. Also try using cat and hexdump
to learn what you can about the file.
Any guesses as to what data is stored in this file?
Don’t read any further until you try to decipher what’s in this file!
Next, determine the size (in bytes) of the lab03-data.dat file. To do so, you can use the ls
command. If you do not already know the flag to use with ls, check out the man page for ls.
Assume that the lab03-data.dat file contains an array of int variables. Write a C program
to read this data file entirely into memory, then display the data using a loop.
To accomplish this, you must call each of the following functions exactly once: calloc(),
fopen(), fread(), and fclose(). In other words, allocate enough memory for this file (you
can hard-code the number of bytes needed), then use only one call to fread() to read in
exactly that number of bytes.
Finally, display the data as follows:
Data point # 0: <int-value>
Data point # 1: <int-value>
Data point # 2: <int-value>

Data point #183: <int-value>
Data point #184: <int-value>
Data point #185: <int-value>
2. Checkpoint 2: Modify your solution for Checkpoint 1 by instead assuming that the given
lab03-data.dat file contains an array of unsigned long variables.
Display the data as follows:
Data point # 0: <unsigned-long-value>
Data point # 1: <unsigned-long-value>
Data point # 2: <unsigned-long-value>

Data point #90: <unsigned-long-value>
Data point #91: <unsigned-long-value>
Data point #92: <unsigned-long-value>
Did you figure out what this data file contains yet?
Note that we can interpret the raw data however we like, treating it as an array of int
values, an array of unsigned long values, a string of printable characters, etc. Only one
interpretation turns out to be correct, though.
3. Checkpoint 3: For the third and final checkpoint, write a C program to read a text file into
memory one line at a time. Use fgets() to accomplish this. And assume a line is no more
than 128 bytes long, meaning you can declare a character array buffer as char line[128].
Next, without using square bracket [] notation or any int (or other numeric) variables whatsoever, traverse each line and display each alphanumeric character you find. To accomplish
this, use pointer arithmetic and the isalnum() function in ctype.h.
At the end of each line, display the total number of alphanumeric characters found on that
line. Use the format shown in the example below. Again, do not use any int or other numeric
variables to accomplish this.
Finally, if no alphanumeric characters are found on a given line, do not display anything, not
even a blank line.
To test your code, start with small test cases, then download the book-1984.txt file and test
with that as input. Your output in this case should start as follows:
PARTONE [7 alnum chars]
Chapter1 [8 alnum chars]
ItwasabrightcolddayinAprilandtheclockswerestrikingthirteen [58 alnum chars]
WinstonSmithhischinnuzzledintohisbreastinanefforttoescapethe [60 alnum chars]
vilewindslippedquicklythroughtheglassdoorsofVictoryMansions [59 alnum chars]
thoughnotquicklyenoughtopreventaswirlofgrittydustfromentering [61 alnum chars]
alongwithhim [12 alnum chars]

HINT: Use pointer arithmetic to achieve this checkpoint.

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