prob d'ouverture de fichier

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

struct dllist {
 char *s;
 struct dllist *next;
 struct dllist *prev;
};

struct dllist *head, *tail;

void append_node(struct dllist *lnode);
void insert_node(struct dllist *lnode, struct dllist *after);
void remove_node(struct dllist *lnode);
void ouvrir(char*mot, FILE **fp);
void utilitaire1(char *argv[],struct dllist *lnode,int pos,int nbr);

int main(int argc, char **argv) {
 struct dllist *lnode;
FILE *fp;char f[100];
int pos,nbr;
 if(3>argc)
{printf("utilisation incorrecte!!!");exit(0);}
ouvrir(argv[1],&fp);
sscanf(argv[3],"%d",&pos);
sscanf(argv[4],"%d",&nbr);
 /* add some numbers to the double linked list */
 while(fgets(f,100,fp)) {
  lnode = (struct dllist *)malloc(sizeof(struct dllist));
  strncpy(lnode->s,f,strlen(f));
  append_node(lnode);
 }
fclose(fp);
 /* print the dll list */
 for(lnode = head; lnode != NULL; lnode = lnode->next) {
  printf("%s\n", lnode->s);
 }
if (strcmp(argv[2],"view")==0) utilitaire1(argv,lnode,pos,nbr);
 /* destroy the dll list */
 while(head != NULL)
  remove_node(head);

 getchar();
return EXIT_SUCCESS;
}

void append_node(struct dllist *lnode) {
 if(head == NULL) {
  head = lnode;
  lnode->prev = NULL;
 } else {
  tail->next = lnode;
  lnode->prev = tail;
 }

 tail = lnode;
 lnode->next = NULL;
}

void insert_node(struct dllist *lnode, struct dllist *after) {
 lnode->next = after->next;
 lnode->prev = after;

 if(after->next != NULL)
  after->next->prev = lnode;
 else
  tail = lnode;

 after->next = lnode;
}

void remove_node(struct dllist *lnode) {
 if(lnode->prev == NULL)
  head = lnode->next;
 else
  lnode->prev->next = lnode->next;

 if(lnode->next == NULL)
  tail = lnode->prev;
 else
  lnode->next->prev = lnode->prev;
}

void utilitaire1(char *argv[],struct dllist *lnode,int pos,int nbr)
{int i,j;
   struct dllist  *courant ;
  for (i = 1; i < pos; ++i)
    courant = courant->next;
    if (pos == i)
    {
        for (j=i;j<nbr;++j)
    printf("%s\n",courant->s); }
}
void ouvrir(char*mot, FILE **fp)
{
if(!(*fp=fopen(mot,"r")))
{
printf("le fichier est inexistant");
exit(0);
}
else printf("ouverture du fichier... \n");
}