C: error: request for member 'next' in something not a structure or union OR error: '-CodePudding

For my linked list, I have the following:

typedef struct node {
  char * value;
  struct node *next;
} NODE;

void delete_nth(NODE **list, int n){
NODE *cur = *list;
int i;                    
if (n == 0){
    printf("\n==========\n");
    list = list->next;
    cur->next = NULL;
    free(cur);
} else {
    for(i = 0; i < n; i  ){
        cur = cur->next;
    }
}
return ;
}

But it returns these errors:

error: '*list' is a pointer; did you mean to use '->'?

error: request for member 'next' in something not a structure or union

What am I doing wrong here?

CodePudding user response：

The problem is NODE **. NODE ** becomes struct node ** which means pointer to pointer to struct node.

The following two lines from your program are not correct:

void delete_nth(NODE **list, int n){
NODE *cur = *list;

These lines should be changed to:

void delete_nth(NODE *list, int n){
NODE *cur = list;

So, now NODE **list is changed to NODE *list and NODE *cur = *list is changed to NODE *cur = list.

CodePudding user response：

This line is not correct:

    list = list->next;

list does not point to a struct but to a pointer to struct. Also you don't want to update list but where list points to.

This would be

    *list = (*list)->next;

If you change list, the calling function would not see it as it is only a copy of the passed value.

Besides this, you forgot to actually remove the nth element after iterating through your list. But that is another topic...