Introduction to UNIX Commands and Basic C Programming Exercises
COMPSCI 210
Semester 1 - 2015
Tutorial 7 – C Exercises
Downloading and unpacking
examples.tar.gz from Cecil
•
Download examples.tar.gz from Cecil into your
hard drive
Downloading and unpacking
examples.tar.gz from Cecil cont.
–
You will be directed to
–
Select unixhome
–
You will be directed to
–
Select Upload File(s)
•
Navigate to where you downloaded examples.tar.gz and upload it
Using University UNIX Account
•
Connect from MS
Windows using Putty
•
All programs -> Putty
•
Under-grad server is
login.cs.auckland.ac.nz
•
Login using your UPI and
password
•
You can access the
machine from home if
you have Putty installed
on your home machine
From: S1-Basic C programming lecture’s slides
Login using your UPI and password
Login using your UPI and password
cont.
Unpacking examples.tar.gz
•
tar xvf examples.tar.gz
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$ ./countdown
Enter a positive number:
6
6
5
4
3
2
1
0
name of source code
name of executatble
From: S1-Basic C programming lecture’s slides
Compile and Run the countdown
Program
Basic Linux Commands
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Creating a directory … mkdir dirname
–
Example: mkdir Assignment3
•
Changing a directory … cd dirname
–
Example: cd Assignment3
–
Going back to the home directory: cd
•
Listing the content of a directory… ls
•
Deleting a directory… rm -rf dirname
–
Example: rm -rf Assignment3 … it deletes the
folder and its contents
Exercise I
Write a C code to
breakdown
www.auckland.ac.nz
web address into:
www
auckland
ac
nz
#include <string.h>
Strtok()
char * strtok (char *restrict newstring, const char *restrict delimiters)
•
A string can be split into tokens by making a series of calls to the function strtok
•
The string to be split up is passed as the newstring argument on the first call only
•
Subsequent calls to get additional tokens from the same string are indicated by passing a null
pointer as the newstring argument
•
The delimiters argument is a string that specifies a set of delimiters that may surround the
token being extracted
•
On the next call to strtok, the searching begins at the next character beyond the one that
marked the end of the previous token
•
Note that the set of delimiters delimiters do not have to be the same on every call in a series
of calls to strtok
•
If the end of the string newstring is reached, or if the remainder of string consists only of
delimiter characters, strtok returns a null pointer.
Retrieved from: http://www.gnu.org/software/libc/manual/html_node/Finding-Tokens-in-a-String.html
Solution
#include <string.h>
#include <stdio.h>
int main()
{char address[40] = "www.auckland.ac.nz";
char delimiter[2] = ".";
char *token;
/* get the first part */
token = strtok(address, delimiter);
/* get the rest */
while( token != NULL )
{printf( " %s\n", token );
token = strtok(NULL, delimiter);
}
return(0);
}
This content guide provides step-by-step instructions on downloading, unpacking, and using examples in UNIX environment, connecting to a university UNIX account from Windows using Putty, logging in with UPI and password, and running basic C programming exercises. It also covers basic Linux commands for creating, changing, listing, and deleting directories.
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Presentation Transcript
COMPSCI 210 Semester 1 - 2015 Tutorial 7 C Exercises
Downloading and unpacking examples.tar.gz from Cecil Download examples.tar.gz from Cecil into your hard drive Go to: http://afsweb.ec.auckland.ac.nz/
Downloading and unpacking examples.tar.gz from Cecil cont. You will be directed to Select unixhome You will be directed to Select Upload File(s) Navigate to where you downloaded examples.tar.gz and upload it
Using University UNIX Account Connect from MS Windows using Putty All programs -> Putty Under-grad server is login.cs.auckland.ac.nz Login using your UPI and password You can access the machine from home if you have Putty installed on your home machine From: S1-Basic C programming lecture s slides
Unpacking examples.tar.gz tar xvf examples.tar.gz
Compile and Run the countdown Program Compile gcc -o countdown countdown.c Run name of executatble name of source code $ ./countdown Enter a positive number: 6 6 5 4 3 2 1 0 From: S1-Basic C programming lecture s slides
Compile and Run the countdown Program
Basic Linux Commands Creating a directory mkdir dirname Example: mkdir Assignment3 Changing a directory cd dirname Example: cd Assignment3 Going back to the home directory: cd Listing the content of a directory ls Deleting a directory rm -rf dirname Example: rm -rf Assignment3 it deletes the folder and its contents
Exercise I Write a C code to breakdown www.auckland.ac.nz web address into: www auckland ac nz
#include <string.h> Strtok() char * strtok (char *restrict newstring, const char *restrict delimiters) A string can be split into tokens by making a series of calls to the function strtok The string to be split up is passed as the newstring argument on the first call only Subsequent calls to get additional tokens from the same string are indicated by passing a null pointer as the newstring argument The delimiters argument is a string that specifies a set of delimiters that may surround the token being extracted On the next call to strtok, the searching begins at the next character beyond the one that marked the end of the previous token Note that the set of delimiters delimiters do not have to be the same on every call in a series of calls to strtok If the end of the string newstring is reached, or if the remainder of string consists only of delimiter characters, strtok returns a null pointer. Retrieved from: http://www.gnu.org/software/libc/manual/html_node/Finding-Tokens-in-a-String.html
Solution #include <string.h> #include <stdio.h> int main() { char address[40] = "www.auckland.ac.nz"; char delimiter[2] = "."; char *token; /* get the first part */ token = strtok(address, delimiter); /* get the rest */ while( token != NULL ) { printf( " %s\n", token ); token = strtok(NULL, delimiter); } return(0); }
