A stack is a data structure that follows the last-in, first-out (LIFO) principle. It allows for two basic operations - push, which adds an item to the top of the stack, and pop, which removes an item from the top. The document provides examples of stacks in real life and defines overflow and underflow situations. It also describes some additional operations that can be performed on a stack like duplicate, peek, swap, and rotate.

2. CREATED BY “SYED SALMAN JILANI“
AND COMPANIONS
GROUPNAME : GUNS & ROSES

3. STACK
TABLE OF CONTENTS
DEFINE STACK
EXAMPLES
OVERFLOW UNDEFLOW
ADDITIONAL OPERATION

4. DEFINE STACK
 A stack is a container of objects that
are inserted and removed according
to the last-in first-out (LIFO) principle
 There are two Basic functions of stack
 PUSH & POP
 Stack is a Limited Access Data structure

5. EXAMPLES
 There are some real life Examples of Stack to
understand its structure
 Stack of Assignment Files Rings Pole and Gun
Magazines

6. OVERFLOW & UNDERFLOW
 A STACK cannot grow indefinitely because there is
always a limit to memory when it comes to limit and yet
another operation tries to PUSH data into the stack then
a stack overflow occurs
 If the stack is Empty and yet a pop operation attempt
this is called underflow
 Additional function are used to stop further PUSH & POP

7. ADDITIONAL OPERATIONS
 Duplicate: the top item is popped, and then pushed again
(twice), so that an additional copy of the former top item is
now on top, with the original below it
 Peek: the topmost item is returned but the stack pointer is not
changed that the item remains on the stack This is also
called top
 Swap or exchange: the two topmost items on the stack
exchange places
 Rotate (or Roll): the n topmost items are moved on the stack
in a rotating fashion.