H
OMEWORK
4 ECS 30-A โ S
PRING
2002
Version of May 13, 2002 8:57 pm Page 1 of 2
Homework 4
Due Date:
Monday, May 27, 2002,
at 11:59PM
Points
: 100
UNIX System
1. (
10 points
) How do I delete the file โi?
2. (
15 points
) Please list all sections of the manual on the CSIF Linux systems containing a command named
time
.
What are the file names of those manual pages?
C Programming
3. (
30 points
) A
palindrome
is a word or sentence which is the same whether read backwards or forwards. Please
write a program ispal.c which reads each line from its standard input and says whether or not the line is a palin-
drome. For each line, all non-alphanumeric characters are to be ignored, and case is not to matter. For example,
standard input standard output
Madam, I'm Adam! A palindrome
O give me a home Not a palindrome
Able was I ere I saw Elba A palindrome
Hint:
use recursion.
4. (
30 points
) Write a program to list the files in a directory in the order in which the directory entries occur. Your
program is to use the library functions
opendir
(3),
readdir
(3), and
closedir
(3). Your output should include the
number of the directory entry, the inode number of the file, and the file name. For example, in a directory contain-
ing the files a.out and d.c, the output might look like:
order inode name
1 1119713 .
2 272679 ..
3 1119719 d.c
4 1119738 a.out
Hint:
On the Linux systems in the CSIF, the inode field of the dirent structure is d_ino. Please see the manual
pages for the functions for more details. (The inode field is
not
documented there, but the field containing the
name of the file is.)
Debugging
5. (
15 points
) On the web page for the class is the source for a set of routines to manage a linked list. The functions
provided are:
int insert(struct link **head, int value)
Insert value into the linked list pointed to by *head; update *head if necessary. If the insertion succeeds, return 1;
if it fails, return 0.
int delete(struct link **head, int value)
Delete value from the linked list pointed to by *head; update *head if necessary (if the list is empty, make it
NULL). If the deletion succeeds, return 1; if it fails (because value is not in the list), return 0.
void prforw(struct link *head)
Print all integers in the linked list pointed to by head in order (from head to tail).
void prback(struct link *head)
Print all integers in the linked list pointed to by head in reverse order (from tail to head).
Unfortunately, they don't quite work right. Debug them. Turn in commented, corrected routines; be sure you
