I'm a Java dev and I'm learning C. I'm working on a project, it's the implementation of tree command from linux in C and I have a simple question. Is this t_node a linked list? It looks like a linked list for me.

This is a part of the code:

struct t_node {
        char* name;
        int  ptd;
        struct t_node *next_dfile;
        struct t_node *next_file;
};

static struct t_node* create_tree(char *root_name) {
        DIR *dir = opendir(root_name);
        struct dirent *dr = {NULL};
        struct t_node *ptr_tstart = NULL,*temp = NULL,*temp1 = NULL;

        char *name = (char *)calloc(2000, sizeof(char));

        if (dir == NULL) {
                printf("\nFailed to open ..!!");
                printf(" : %s", root_name);
                return NULL;
        }

        while ((dr = readdir(dir)) != NULL) {
                if (strcmp((dr->d_name), ".") != 0 && strcmp((dr->d_name), "..") != 0) {
                        temp = create_tnode(dr->d_name);
                } else {
                        temp = NULL;
                        continue;
                }

                if (temp1 != NULL) {
                        temp1->next_file = temp;
                } else {
                        (ptr_tstart) = temp;
                }

                if ((dr->d_type) == DT_DIR) {
                        temp->ptd = TRUE;
                        strcpy(name, root_name);
                        (temp->next_dfile) = create_tree((strcat((strcat(name, "/")), dr->d_name)));
                        strcpy(name, root_name);
                } else {
                        (temp)->ptd = FALSE;
                        (temp)->next_dfile = NULL;
                }
                temp1 = temp;
        }
        return (ptr_tstart);
}


static struct t_node* create_tnode(char* n) {
        struct t_node *temp = (struct t_node *)malloc(sizeof(struct t_node));

        temp->name = n;
        temp->next_dfile = NULL;
        temp->next_file = NULL;

        return temp;
}

t_node will be a file or directory, if ptd is true then it is a directory. next_file will be the next file/directory in the same directory and next_dfile will be the next file/folder inside a directory.

We have music_dir with rock and disco files and movie_dir with drama and thriller files. mudic_dir will have movie_dir as next_file. And music_dir will have rock as next_dfile, and rock will have disco as next_file, etc.

I just want to know if this t_node is a linked list. Thank you!

CodePudding user response：

It's a tree.

The pointers to the siblings are stored in a linked-list. But overall, you have a tree.

                            |
                            v
                           ---    ---    --- 
                          |   |->|   |->|   |
                           ---    ---    --- 
                            |      |      |
                 -----------       |       ---------------- 
                |                  |                       |
                v                  v                       v
          ---    ---    ---       ---    ---    ---       ---    ---    --- 
         |   |->|   |->|   |     |   |->|   |->|   |     |   |->|   |->|   |
          ---    ---    ---       ---    ---    ---       ---    ---    --- 
           |      |
   --------        ------- 
  |                       |
  v                       v
 ---    ---    ---       ---    ---    --- 
|   |->|   |->|   |     |   |->|   |->|   |
 ---    ---    ---       ---    ---    ---