Inserting item into a linked list - c

Question

I'm trying to add to my linked list only if the item I'm inserting isn't already in the link list but when I try to traverse it and print out all of the items nothing is printing out. I can't seem to see what I'm doing wrong. Any help would be appreciated
// my add function
void add(char *val)
{
printf("%s", val);// val is getting printed so i know its being passed in.
if(head == NULL){
struct node *new_node = (struct node *)malloc(sizeof(struct node));
head = new_node;
head->item = val;
head->next = NULL;
} else{
struct node *current = head;
struct node *newNode = (struct node *) malloc(sizeof(struct node));
if (newNode == NULL) {
exit(-1);
}
newNode->item = val;
newNode->next = NULL;
while (current != NULL) {
current = current->next;
}
current = newNode;
}
}
//my traverse function
void goThroughList() {
struct node *current = head;
while(current != NULL){
printf("%s\n",current->item);
current= current->next;
}
}

Answer 1

add doesn't successfully add anything once head has been assigned. It only updates a local current pointer. You could fix that by changing the code that searches for the tail of the list to
while (current->next != NULL) {
current = current->next;
}
current->next = newNode;
If this doesn't help, can you update your question to show how add is being called? (To rule out the possibility that the same char array is being used for multiple calls, leaving all nodes with their item pointers pointed to the same buffer.
Also, there is no code I can see that checks for duplicates. You could implement this inside the branch of add where head already existed by iterating through the list using strcmp to compare each node's item with val.

Answer 2

your add function is incorrect
try this one :
void add(char *val)
{
printf("%s", val);// val is getting printed so i know its being passed in.
if(head == NULL){
struct node *new_node = (struct node *)malloc(sizeof(struct node));
new_node->item = val;
new_node->next = NULL;
head = new_node;
}
else{
struct node *current = head;
while (current->next != NULL) {
if(strcmp(current->item, val) == 0)
return;
current = current->next;
}
struct node *new_node = (struct node *)malloc(sizeof(struct node));
new_node->item = val;
new_node->next = NULL;
current->next = new_node;
}
}

Answer 3

what list does this function go trought ?
void goThroughList() {
struct node *current = head;
while(current != NULL){
printf("%s\n",current->item);
current= current->next;
}
}
try this instead :
void goThroughList(struct node* llist)
{
if(llist)
{
printf("%s" , llist->item);
goThroughList(llist->next);
}
}