c - How to use fscanf to read a line to parse into variables? -

i'm trying read text file built following format in every line, example:

a/a1.txt a/b/b1.txt a/b/c/d/f/d1.txt 

using fscanf read line file, how can automatically parse line variables of *element , *next, each element being path section (a, a1.txt, b, c, d1.txt , on).

my structure follows:

struct mypath {     char *element;  // pointer string of 1 part.     mypath *next;   // pointer next part - null if none. } 

you better off using fgets read entire line memory, strtok tokenise line individual elements.

the following code shows 1 way this. first, headers , structure definintion:

#include <stdio.h> #include <stdlib.h> #include <string.h>  typedef struct smypath {     char *element;     struct smypath *next; } tmypath; 

then, main function, creating empty list, getting input user (if want robust input function, see here, follows below cut down version of demonstrative purposes only):

int main(void) {     char *token;     tmypath *curr, *first = null, *last = null;     char inputstr[1024];      // string user (removing newline @ end).      printf ("enter string: ");     fgets (inputstr, sizeof (inputstr), stdin);     if (strlen (inputstr) > 0)         if (inputstr[strlen (inputstr) - 1] == '\n')             inputstr[strlen (inputstr) - 1] = '\0'; 

then code extract tokens , add them linked list.

    // collect tokens list.      token = strtok (inputstr, "/");     while (token != null) {         if (last == null) {             first = last = malloc (sizeof (*first));             first->element = strdup (token);             first->next = null;         } else {             last->next = malloc (sizeof (*last));             last = last->next;             last->element = strdup (token);             last->next = null;         }         token = strtok (null, "/");     } 

(keeping in mind strdup not standard c can find a decent implementation somewhere). print out linked list show loaded properly, followed cleanup , exit:

    // output list.      (curr = first; curr != null; curr = curr->next)         printf ("[%s]\n", curr->element);      // delete list , exit.      while (first != null) {         curr = first;         first = first->next;         free (curr->element);         free (curr);     }      return 0; } 

a sample run follows:

enter string: path/to/your/file.txt [path] [to] [your] [file.txt] 

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i should mention that, while c++ allows leave off struct keyword structures, c not. definition should be:

struct mypath {     char *element;         // pointer string of 1 part.     struct mypath *next;   // pointer next part - null if none. };