Function: InsertEnd(X, FIRST)
- This function inserts a new node at the last position of linked list.
- This function returns address of FIRST node.
- X is a new element to be inserted.
- FIRST is a pointer to the first element of a Singly linked linear list.
- Typical node contains INFO and LINK fields.
- AVAIL is a pointer to the top element of the availability stack.
- NEW is a temporary pointer variable.
Function: POP( FIRST)
- This algorithm deletes and returns First Node from Singly Linked List.
- FIRST is a pointer to the first element of a linked linear list.
- Typical node contains INFO and LINK fields.
1. [Underflow?]
If AVAIL = NULL
Then Write (“Availability Stack Underflow”)
Return(FIRST)
2. [Obtain address of next free Node]
NEW<--AVAIL
3. [Remove free node from Availability Stack]
AVAIL<--LINK(AVAIL)
4. [Initialize field of NEW node]
INFO (NEW) <-- X
LINK (NEW) <-- NULL
5. [Is the list empty?]
If FIRST = NULL
Then Return (NEW)
6. [Initialize search for a last node]
SAVE <-- FIRST
7. [Search for end of list]
Repeat while LINK (SAVE) ? NULL
SAVE <-- LINK (SAVE)
8. [Set link field of last node to NEW]
LINK (SAVE) <-- NEW
9. [Return first node pointer]
Return (FIRST)
When INSERTEND is invoked it returns a pointer value to the variable FIRST
FIRST <-- INSERTEND (X, FIRST)
