ls.c

#include <dirent.h>
#include <stdio.h>
int main(int argc, char *argv[])
{
  DIR *dir;
  struct dirent *de;
  if (argc > 1)
    dir = opendir(argv[1]); /*your directory*/
  else
    dir = opendir("."); /* Default: current path */
  while (dir)
  {
    de = readdir(dir);
    if (!de)
      break;
    printf("%s\n", de->d_name);
  }
  closedir(dir);
  return 0;
}