Help with linked list (and reading user input)

Hi i have two basic functions

Code:

llnode* createList(){
 
 char tmp;
 llnode *head = NULL;
 if ((head =(llnode *) malloc(sizeof(llnode))) == NULL) {
      (void)exit();
    }  
 while((tmp = getchar()) != '\n'){
    add(&head,(int)(tmp-'0'));
    }
    
 return head;
}

that creates a list by reading in user input and then calling add which adds it to the list

add:

Code:

void add(llnode **head, int data_in) {
    llnode *tmp;
    if ((tmp =(llnode*) malloc(sizeof(llnode))) == NULL) {
      (void)exit();
    }
    tmp->digit = data_in;
    tmp->next = *head;
    *head = tmp;
  }

For some reason when i run this I ask the user to input a number so say they type in "2221" it will add everythingto the list however it adds a zero aswell for some reason. So my lists is
"12220" when i print it out. Any ideas? Thx.

perhaps you could try to wrap them all in one function (untested code):

Code:

llnode *head = NULL;

void create_list()
{
    llnode *tmp;
    llnode *ptr;
    char c;

    while( (c = getchar()) != '\n' && c != EOF )
    {
        if ( (tmp = malloc( sizeof(llnode) )) == NULL)
            exit();
        tmp->digit = c;
        tmp->next = NULL;

        ptr = head;
        if (ptr == NULL)
        {
            ptr = tmp;
        }
        else
        {
            while( ptr->next != NULL )
                ptr = ptr->next;

            ptr->next = tmp;
        }
    }
}

> So my lists is "12220" when i print it out. Any ideas?
Yes, it's the dummy (and useless) node you add at the start.

All you need is

Code:

 llnode *head = NULL;
 while((tmp = getchar()) != '\n'){
    add(&head,(int)(tmp-'0'));
    }

Oh, and drop all those casts of malloc - see the FAQ for why.

I don't know why you're casting the "result" of exit() either, since it doesn't return.