LinkedList functions crash in c - c

Question

I implemented a linked list in c. when i test it, whenever i reach display function or insert at the end the program crashes. These are the functions:
struct Node
{
char data;
struct Node *next;
};
struct LinkedList
{
struct Node *head;
};
void insertAtBeginning(struct LinkedList *LL, char ele)
{
struct Node *new = (struct Node*)malloc(sizeof(struct Node));
new->data = ele;
new->next = NULL;
if(new->data == '\n')return;
if(LL->head==NULL)LL->head = new;
else
{
new->next=LL->head;
LL->head=new;
}
}
void insertAtTheEnd(struct LinkedList *LL, char ele)
{
struct Node *new = (struct Node*) malloc(sizeof(struct Node));
new->data = ele;
new->next = NULL;
if(LL->head==NULL){LL->head=new;return;}
struct Node *current = LL->head;
while(current->next != NULL) {current = current->next;}
current->next = new;
}
void deleteNode(struct LinkedList* LL, char ele)
{
struct Node *current = LL->head;
struct Node *temp = LL->head;
while(current->next->data!=ele && current!=NULL)current=current->next;
temp=current->next;
current->next=current->next->next;
free(temp);
}
void deleteFirstNode(struct LinkedList* LL)
{
struct Node *temp;
if(LL->head != NULL)
{
temp = LL->head;
LL->head = LL->head->next;
free(temp);
}
}
void displayLinkedList(struct LinkedList LL)
{
struct Node *current = LL.head;
printf("List: ");
while(current != NULL)
{
printf("%c",current->data);
current = current->next;
}
printf("\n");
}
This is the main:
main()
{
struct LinkedList LL;
char c = '0';
//Inserting at beginning
printf("Type a string. Press Enter to end: ");
while(c != '\n')
{
scanf("%c",&c);
insertAtBeginning(&LL, c);
}
printf("List: ");
displayLinkedList(LL);
printf("\n");
//Inserting at end
c='0';
printf("Type a string. Press Enter to end: ");
while(c != '\n')
{
scanf("%c",&c);
insertAtTheEnd(&LL, c);
}
printf("List: ");
displayLinkedList(LL);
printf("\n");
//Remove
printf("Enter a char to remove: ");
scanf("%c",&c);
deleteNode(&LL, c);
printf("\n");
printf("List: ");
displayLinkedList(LL);
printf("\n");
deleteFirstNode(&LL);
printf("List: ");
displayLinkedList(LL);
}
of course This is done after inserting the necessary libraries.

Answer 1

you have to set NULL to next when you create element. if you do not do it, your while loop behaviour will be buggy
void insertAtTheEnd(struct LinkedList *LL, char ele)
{
struct Node *new = (struct Node*) malloc(sizeof(struct Node));
new->next = NULL;
new->data = ele;
if(LL->head == NULL) LL->head = new;
else
{
struct Node *current = LL->head;
while(current->next != NULL) {current = current->next;}
current->next = new;
}
}
, and do same for other functions.
also you have to set NULL to your LinkedList.head. so, set NULL when you define LinkedList
struct LinkedList LL;
LL.head = NULL;

Answer 2

i asume the line if(current = LL->head) is wrong
bacause temp = current->next would crash if the result is NULL
otherwise the code after the if statement doesnt makes sense

Answer 3

There are some instances where you will try to insert at the end. When you have something of the form node_new->next->prev = node, you must check to make sure that node_new->next is not NULL, because NULL does not have any type and thus does not have a prev field.
You may also consider making all of your functions return int, so that you can know if and what goes wrong.