The document discusses stacks, which are linear data structures that follow the LIFO (last in first out) principle. Elements are inserted and deleted from one end called the top. The two main operations on a stack are push, which inserts an element, and pop, which deletes the top element. When pushing a new element, the stack must check for overflow if the top is already at maximum capacity. When popping an element, underflow occurs if trying to pop from an empty stack.

2. Stack (LIFO)last in first
out.
Linear collection of data
elements.
Insertion and deletion
take place only at one
end(TOP).
Insertion operation is

3. There are two operations
implement on stack:-
1. Push(insert)
2. Pop(delete)

4.  Deletion operation is called
pop operation in stack.
 Stack is restricted kind of
data structure.
 Ex:-

5. To add a new element in
stack . This operation is
called push in stack . If we
want to push element in
stack first of all we have to
check condition “overflow”.

6. Overflow means if TOP of
stack is equal to MAXSTACK
and we want to add new
element into a stack then a
condition “overflow” is occur.
ex:- Here
top=5
Maxstk =5
So” overflow condition
occur”
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7. To remove existing element
from stack . This operation is
called pop in stack . If we want
to pop element in stack first of
all we have to check condition
“underflow”.

8. Underflow means if top=0
or top=null and we want to
delete element from stack
then the condition
“underflow” is occur. Ex:-
Here
Top=0
Maxstk =5
So condition “underflow”
Occur.
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9. Thanks