1. STACK
By:- Rajendra ShakyawalP.G.T. Computer Science KV-No.1, AFS, Tambaram, Chennai

2. STACK Using Linked List What is Stack ?
Operation on Stack … ( PUSH and POP)
Applications of Stack

3. STACK
A stack is a LIFO structure and physically it can be implemented as an array or as a linked list.
A stack is implemented as an array that inherits all the properties of an array and if implemented as a linked list , all characteristics of a linked list are possessed by it.
top S T A C K

4. OPERATIONS ON STACK
A stack is generally implemented with two basic operations- Push and Pop.
Whatever way a stack may be implemented, insertion (push) and deletions (POP) occur at the top only.
Push – Allows adding an element at the top of the Stack.
Pop - Allows to remove an element from the top of the Stack.

5. Stack Operations (PUSH , POP) Example
top 6

6. Stack Operations (PUSH , POP) Example
top 1 6

7. Stack Operations (PUSH , POP) Example7
top 1 6

8. Stack Operations (PUSH , POP) Example8 7
top 1 6

9. Stack Operations (PUSH , POP) Example8 7
top 1 6

10. Stack Operations (PUSH , POP) Example7
top 1 6

11. CREATING A STACK (LINKED STACK)
The creation of a stack ( as a linked list) is the same as the creation of a linked list i.e., after getting a new node, TOP point to the newly inserted node.

12. Creating a Node for Stack
struct stack { int info;
stack *next;
} *top, s;
Info
next S

13. INSERTION IN A LINKED STACK (PUSH)
TOP
Fig A 44
55 n
TOP 33 44
55 n
Fig B
TOP 22 33 44
55 n
Fig C
As a push can only occur at the TOP gets modified every time.
For instance, if we have a stack as shown in fig (a) after pushing 33 , it becomes as Fig (b). After pushing another element 22, it becomes as Fig (c).

14. DELETION (POP) FROM A LINKED STACK
TOP 22 33 44
55 n
Fig A
TOP 33 44
55 n
Fig B
TOP 44
55 n
Fig C
Deletion i.e. popping also require modification of TOP i.e. TOP is made to point to the next node in the sequence. For instance, if the stack is shown in Fig a; after popping 22 , it becomes as Fig b. After Popping 33 , it becomes a Fig c.

15. Application of Stack Reversing a Line POLISH NOTATION
CONVERSION OF INFIX EXPRESSION TO POSTFIX (SUFFIX) EXPRESSION

16. THANK YOU