Programming

I am making a program in c. I want the progrm to be able to display file names ( like in unix we do long lisiting)

what should i do?

Any help will be appreciated

With the system() command?
The other way is to use functions like opendir, lstat and structs like dirent, stat etc..

Code:

man 2 stat
man dirent

I am going to run this prgm in unix

Code:

/*
** mydirDisplay.c
*/

#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>

int
main(int argc, char *argv[])
{
   struct dirent *ent;
   DIR *dir;

   if (argc == 2) {
       if ((dir = opendir(argv[1]))) {
           while((ent = readdir(dir)) != NULL)
               fprintf(stdout, "%s\n", ent->d_name);
       } else
           fprintf(stderr, "Error opening directory %s\n", argv[1]);
   }

   return 0;
}

What this code does it that it takes the command line argument as the input directory and opens the same using opendir() system call; on sucess of this sys call it reads the directory entaties using readdir() syscall and prints the same on the stdout untill it encounters NULL.

Now what you need to do is run the following command on your Linux system prompt:

$ gcc mydirDisplay.c -o myls

and
$ ./myls <some directory Path>

You may also put it at either /bin directory, if you have root access, or in any directory but add the path to your environmental PATH variable; and this becomes your command.

Do add features like other swtiches of the ls command (e.g. -l, -a etc...) and instead of depending on the argc, argv only, try using getopt() ... look at the man pages of getopt() and also improve the display fprintf(stdout, ...) to look like what 'ls' prints on the stdout as a task for you. Let me know if you have any other queries.