Linked List Operations

Linked List Operations

Linked List operations are as follows

• Traversal – Access the nodes of the list.
• Insertion – Adds a new element to an existing linked list.
• Deletion – deletets a node from an existing linked list.
• Search – search a particular element in the linked list

1. Traverse a Linked List

Traversing is a accessing the nodes of a linked list in order to process

Algorithm of traversing the linked list

Step 1: [INITIALIZE] SET PTR = HEAD
Step 2: Repeat Steps 3 and 4 while PTR != NULL
Step 3:     Apply process to PTR -> DATA
Step 4:     SET PTR = PTR->NEXT
        [END OF LOOP]
Step 5: EXIT

Program of traversing the linked list

struct node *temp = head;
printf("\n\nList elements are - \n");
while(temp != NULL) {
  printf("%d --->",temp->data);
  temp = temp->next;
}

Output

List elements are - 
1 --->2 --->3 --->

2. Insert Elements to a Linked List

There are three cases to inserting element in linked list

struct node *newNode;
newNode = malloc(sizeof(struct node));
newNode->data = 4;
newNode->next = head;
head = newNode;

struct node *newNode;
newNode = malloc(sizeof(struct node));
newNode->data = 4;
newNode->next = NULL;

struct node *temp = head;
while(temp->next != NULL){
  temp = temp->next;
}

temp->next = newNode;

3. Insert at the given node

Allocate memory and store data for new node and traverse to node one before the required position of new node after that change next pointers to include new node in between

Block of code of insert at given node

struct node *newNode;
newNode = malloc(sizeof(struct node));
newNode->data = 4;

struct node *temp = head;

for(int i=2; i < position; i++) {
  if(temp->next != NULL) {
    temp = temp->next;
  }
}
newNode->next = temp->next;
temp->next = newNode;

3. Delete from a Linked List

1. Delete from beginning

Point head to the next  node

head = head->next;

2. Delete from end

Traverse to second last element and change next pointer to null

struct node* temp = head;
while(temp->next->next!=NULL){
  temp = temp->next;
}
temp->next = NULL;

3. Delete from middle

Traverse to element before the element to be deleted and change next pointers to ecxcept the node from the chain

for(int i=2; i< position; i++) {
  if(temp->next!=NULL) {
    temp = temp->next;
  }
}

temp->next = temp->next->next;

Read more, Linked List Data Structure