1. COMPSCI 210 Semester 1 - 2015 Tutorial 7 – C Exercises

2. 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/http://afsweb.ec.auckland.ac.nz/

3. 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

4. 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

5. Login using your UPI and password

6. Login using your UPI and password cont.

7. Unpacking examples.tar.gz tar xvf examples.tar.gz

8. Compile and Run the countdown Program Compile gcc -o countdown countdown.c Run $./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

9. Compile and Run the countdown Program

10. 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

11. Exercise I Write a C code to breakdown www.auckland.ac.nz web address into: www auckland ac nz

12. #include 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

13. Solution #include 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); }