CIS 361
Name: Last, First March:30
Quiz #2
•This classroom has enough seats for you to sit with no one laterally adjacent to you; please
do so.
•During this test, you should not use any auxiliary materials or computational devices;
i.e. this test is ‘closed-book’ (and ‘closed-notes’ etc.). But if you can’t remember some little
detail, ask the instructor.
•If your handwriting really is poorly legible, up to one point may be subtracted from your
score.
A. [128 points] Write a complete C program like what I’ve been using in lectures to
randomly choose people to call on. (Your program here does not need to do everything
like mine; in particular, your program does not need to modify any ‘count’ values in the
data file.) A data file for your program here would appear like the following:
count name
===== ====
13 BROWN,TERRY
14 JONES,SAM
12 LEE,CHRIS
13 SMITH,PAT
. .
. .
. .
Your program needs to skip over the header-material at the beginning of the file (through
the line beginning with “=”, which you explicitly need to check for because the number of
header lines can vary, not being just 2), randomly and fairly select one of the remaining
lines, and output the second field of the selected line — “LEE,CHRIS” or “BROWN,TERRY”
or . . . (Don’t worry about finding a line containing a low value.) The number of lines in
the file needs to be determined by reading the file; it cannot be determined any other way.
And then after that, without opening the file again, you’ll need to return to the beginning
of it to re-find a selected line.∗(Do not try to store the entire contents of a file in memory.)
Error-check program-arguments and file-access as usual, using standard error output and
setting the exit-status value as appropriate. Also, use fgets() for reading, and use a
named constant for the size of your line-buffers.
∗Actually, as my program does, even without reopening the file, you can do the random, fair selection
without needing to return to the beginning of the file. If you figure out how to do this, fine; but otherwise,
you need to return to the beginning of the file.
page 1 of 4
