Description
Introduction
The objective of this assignment is to understand basic File I/O on the system level.
You should use only ““`create()“`, “`open()“`, “`close()“`, “`write()“`, “`read()“`, “`lseek()“`”.
Please read Chapter 10 “System level I/O” of “Computer Systems: A Programmer’s Perspective” before doing this assignment.
Specification
The command line typed by the user should consist of a command name and zero or more arguments, all seperated by one or more spaces.
You should complete four function.
* “`create_file(char* filename)“`
* create file named filename. Be careful about the permission of your file.
* “`write_file(char* filename, char* tmp)“`
* Write the contents of the tmp array to a file named filename.
* Suppose the size of the tmp is less then 10 bytes.
* If there is no such file, create new file.
* If there already exist such file, erase the original contents and overwrite it.
* “`read_file(char* filename, int size)“`
* Read a function that reads a file of a given size and print it.
* If there is no such file, print “error occured\n”.
* “`weird_copy_file(char* source, char* dest, int n)“`
* This function copy the source file with weird manner. It copy back and forth as much as n byte in iterative way.
* See the example below to understand this function.
* ex) n = 4, source file : “1234abcd” then contents of dest file will be “1a2b3c4d”.
* ex) n = 2, source file : “12AB” then contents of dest file will be “1A2B”.
* ex) n = 1, source file : “12” then contents of dest file will be “12”.
* **notice** : the goal of this function is to understand how “`lseek()“` works. You can solve it in a different way, but you have to use “`lseek()“`.
You can’t see your file when you creating your file.
If you want to check your files in your console, use another function you did in your last assignment.
Output example
“`
create foo.txt
write foo.txt hello
read foo.txt 5
5 hello
read foo.txt 3
3 hel
read test.txt 1
error occured
create test.txt
write foo.txt 1234abcd
copy foo.txt test.txt 4
read test.txt 8
8 1a2b3c4d
“`
Evaluation
Your score will be computed out of a maximum 100 points with several test cases.
We will evaluate your score on elice evaluation system.
If you copy codes from internet or from other students, you will get 0 points.
