Algorithm for the print the doubly list

Procedure PRINT (TEMPHEAD)

[This procedure print the element of the node in the LIFO and FIFO format and TEMPHEAD points the first element of the list]

1. [Check for the empty list]

          If TEMPHEAD = NULL

                   Then write (“Empty list”)

                   Return

2. [First in first out]

          Repeat while RPTR (TEMPHEAD)! = NULL

                   Write (INOF (TEMPHEAD))

3. [Last in first out]

          Repeat while TEMPHEAD! = NULL

                   Write (INFO (TEMPHEAD))

4. [Finished]                  

            Return                        

Algorithm for the deleting an element from the doubly linked list

Function DELETE (TEMPHEAD, KEY)

[This Function delete an element from the doubly list and returns the address of the first element TEMPHEAD is pointer which points the first element of the list and KEY specify info of the node which is to be deleted]

1. [Check for the empty list]

          If TEMPHEAD = NULL

                   Then write (“Empty list”)

                   Return

2. [Deletion of the first node]

          TEMP = TEMPHEAD

          RPTR (TEMPHEAD) = TEMPHEAD

          PRV (TEMPHEAD) = NULL

          Free (TEMP)

          Return (TEMPHEAD)

3. [Save the address of the first node]

          SAVE = TEMPHEAD

4. [Search for the desire node]

          Repeat while thru step 5 RPTR (SAVE)! = NULL

5. [Check for the information field]

          If INFO (RPTR (SAVE)) = KEY

                   Then   TEMP = RPTR (SAVE)

                               RPTR (SAVE) = RPTR (RPTR (SAVE))

                               LPTR (RPTR (SAVE)) = SAVE

                               Free (TEMP)

6. [Finished]

          Return (TEMPHEAD)

Algorithm for the insert an element in the doubly list

Function INSERT (TEMPHEAD, KEY)

[This Function inserts an element after the node which the info filed equals to the KEY and the returns the address of the first node]

1. [Allocate the memory for the new node]

          NEW          NODE

          INFO (NEW) = X

2. [Insertion as the first node]

          RPTR (NEW) = TEMPHEAD

          LPTR (NEW) = NULL

          RPTR (TEMPHEAD) = NEW

          TEMPHEAD = NEW

          Return (TEMPHEAD)

3. [Save address of the first node]

          SAVE = TEMPHEAD

4. [Find the element after which we want to insert the element]

          Repeat thru step while RPTR (SAVE)! = NULL

5. [Check for the desire position]

          If INFO (RPTR (SAVE)) = KEY

                   Then

                             RPTR (NEW) = RPTR (SAVE)

                             LPTR (NEW) = SAVE

                             LPTR (RPTR (SAVE)) = NEW

                             RPTR (SAVE) = NEW

6. [Finished]

          Return (TEMPHEAD)

Algorithm for the Creation of the Doubly linked list

Procedure CRETE(TEMPHEAD)

[This Procedure Create the Doubly linked list TEMPHEAD is the pointer variable which point to the first element of the list and LPTR and RPTR is the pointer field of the NODE which points the Previous and new Node of the list respectively.]

1. [Repeat thru step]

          Repeat while choice! = ‘n’

2. [Allocate the new Node]

            NEW          NODE

3. [Set field of new Node]

          INFO (NEW) = X

          LPTR (NEW) = RPTR (RPTR) = NULL

4. [Insert the element]

          RPTR (TEMPHEAD) = NEW

          LPTR (RPTR (TEMPHEAD)) = TEMPHEAD

          TEMPHEAD = RPTR (TEMPHEAD)      

5. [Read the Choice]

          Read (choice)

6. [Finished]

Algorithm for the print the list

Procedure PRINT (HEAD)

[This Procedure print the information field of the list and HEAD is the first element of the list]

1. [Repeat step thru]

          Repeat while LINK (HEAD) != NULL

2. [Print the Information]

          Write (INFO (HEAD))

3. [Finished]

          Return

Algorithm for the delete the element from the list

Function DEL (TEMPHEAD, KEY)

 [This Function Delete the Node whose information fields equals to the KEY. And TEMPHEAD is the pointer which points the first element of the list and function returns the address of the first node]          

1. [Check for the empty list]

          If TEMPHEAD = NULL

                   Then write (“Empty List”)

2. [Deletion of the first node]

          SAVE = TEMPHEAD

          TEMPHEAD = LINK (TEMPHEAD)

          Free (SAVE)       

          Return (TEMPHEAD)

3. [Save the address of the first node of the list]

          SAVE = TEMPHEAD

4. [Find the Node which to be deleted]

          Repeat while INFO (LINK (SAVE))! = KEY 

5. [Delete the node]

          TEMP = LINK (SAVE)

          LINK (SAVE) = LINK (LINK (SAVE))

           Free (TEMP)

6. [Finished]

          Return (TEMPHEAD)

Algorithm for the Inserting the element in the Simple Linked List

Function INSERT (TEMPHEAD,KEY)

[This Function Insert the element after the node, which have the information field equal to the X. And HEAD is the pointer variable, which points to the first element of the list]

1. [Allocate the Memory for the NEW node]

          NEW          NODE

2. [Set fields of the NEW node]

          INFO (NEW) = X

          LINK (NEW) = NULL

3. [Insertion as the first node]

          LINK (NEW) = TEMPHEAD

          TEMPHEAD = NEW

          Return (HEAD)

4. [Save the address of the first element of the list]

          SAVE = TEMPHEAD  

5. [Find the element after which we want to insert the element]

          Repeat while INFO (LINK (SAVE) ) != NULL

6. [Insert the element]

          LINK (NEW) = LINK (SAVE)

          LINK (SAVE) = NEW

7. [Return the address of the first element]

          Return (TEMPHEAD)

Algorithm for the Creation of the Simple Linked List

Function CREATE(X, FIRST)

[Given X, a new element, and FISRT, a pointer to the first element of a Linked linear list whose typical node contains INFO and LINK fields as in above fig, this function inserts X.]

1. [Repeat thru step 5]

          Repeat while Choice! = ‘n’

         

2. [Allocate the New node]

          NEW          NODE

3. [Initialize the fields of new node]

          INFO (NEW) = X

          LINK (FIRST) = NEW

4. [Want to insert another node]

          Read (Choice)

5. [Set the LINK field of Last inserted element]

          LINK (FIRST) = NULL

6. [Finished]

          Return