LINKED LIST
What is Linked list ? Just as the name suggests LINKED LIST it is a list of data that is connected in a such a way that the address of next element or data is stored in the previous data . To access the linked list all we need to do is access the address of first element and that will automatically print the whole list ( because every element is connected with each other).
Why do we use it ? As we know in ARRAY we can store data of similar data type. So array has this con that it can only store data of similar data type. So to overcome this we introduced Linked List . A linked List can store data of multiple data types . This is the main advantage of using a Linked List . Another advantage of using Linked List is the operation of insertion and deletion become easy. Because a LINKED LIST IS MADE UP OF VARIOUS *NODES ( A Node is nothing but it is a structure that holds a data of any data type and Address of type structure). How to use it ? Declaration: struct Linked_List { int Data; struct Linked_List *Node; } This structure has data of data type int and its second variable of struct type Linked_List *Node is used to hold the address of next variable . For making a linked list we need to malloc (to allocate the memory for every node) every single node. As many elements as we want to enter.
-----IMP---- The head node of a linked list should be fixed so that we can access whole Linked list. If we will delete the Head node of the linked list the whole linked list will get destroyed and will get lost in the memory space (as observed) . To End a Linked list we must need to store the Null instead of address so that it won’t access any other . Figure
Head Node
End Node
Operations we can perform
We can perform various operations like insertion , deletion and sorting etc. To perform any operation first we have to know about the position the pointer where it actually is present , which element or node is it representing at present . While making a head node we introduce a variable of type structure that is defined above named temp . All the operations that we want to perform on linked list is performed by the help of temp variable . We never move head node anywhere (Head node is fixed ) . According to our operation we write algo and make functions .
Techniques Using Linked List Stacks – Works on LIFO Technique (Last In First Out) Queues – Works on FIFO Technique (First In First Out)
Types of Linked List Singly Linked List – In this each node has data and pointer pointing towards next Node . As mentioned above in Figure . Doubly Linked List - In this we add a pointer to the previous node . Thus we can go in both forward and backward direction
Circular Linked List – In this the end node of Linked list holds the address of the head node . So it makes up a circle .