Shuffles and outputs a list of .txt files in the pwd.

shuffler.c

// TXT Shuffler by FelicitusNeko is marked with CC0 1.0.
// To view a copy of this license, visit https://creativecommons.org/publicdomain/zero/1.0/

#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

typedef struct listing_t {
  char *name;
  struct listing_t *next;
} LISTING;

int main(void) {
  struct dirent *de;
  DIR *dr = opendir(".");
  LISTING *item = NULL;
  int count = 0;

  if (dr == NULL)
  {
    printf("Could not open current directory\n");
    return 1;
  }

  while ((de = readdir(dr)) != NULL) {
    //// Following two lines work in Linux but not Windows.
    // if (de->d_type != DT_REG) continue;
    // size_t namelen = strlen(de->d_name);
    size_t namelen = de->d_namlen;
    if (namelen < 4) continue;
    if (strncmp(&de->d_name[namelen - 4], ".txt", 4)) continue;
    if (!strncmp(de->d_name, "LIST__", 6)) continue;

    LISTING *newitem = malloc(sizeof(LISTING));
    newitem->name = malloc(sizeof(char) * namelen + 2);
    strncpy(newitem->name, de->d_name, namelen + 1);
    newitem->next = item;
    item = newitem;
    count++;
  }

  closedir(dr);
  if (item == NULL) {
    printf("No items in list\n");
    return 2;
  }

  time_t t = time(NULL);
  struct tm *lt = localtime(&t);
  char listfile[33] = {0};
  snprintf(listfile, 32, "LIST__%d_%02d_%02d__%02d_%02d_%02d.txt",
    lt->tm_year + 1900, lt->tm_mon + 1, lt->tm_mday, lt->tm_hour, lt->tm_min, lt->tm_sec);

  FILE *listfile_h = fopen(listfile, "w");
  srand(t);

  while (item != NULL) {
    int getitem = rand() % count;
    LISTING *delitem = item;

    if (getitem == 0) {
      item = item->next;
    } else {
      for (int x = 1; x < getitem; x++){
        delitem = delitem->next;
      }

      LISTING *previtem = delitem;
      delitem = delitem->next;
      previtem->next = delitem->next;
    }

    fprintf(listfile_h, "%s\n", delitem->name);
    free(delitem->name);
    free(delitem);
    count--;
  }

  fclose(listfile_h);

  return 0;
}