2. The stack is a very common and non
primitive data structure used in
programs. By data structure, I mean
something that is meant to hold data
and provides certain operations on
that data.
3. Abstract definition
• A stack is a fundamental computer
science data structure and can be defined
in an abstract, implementation-free
manner,
• it can be generally defined as,
Stack is a linear list of items in which all
additions and deletion are restricted to
one end that is Top.
5. Operations on stack
• a stack is a last in, first out (LIFO) abstract data
type and Data structure
In computer science, a data structure is a particular
way of storing and organizing data in a computer
so that it can be used efficiently .Different kinds of
data structures are suited to different kinds of
applications, and some are highly specialized to
specific tasks...
A stack can have any abstract data type as an
element, but is characterized by only three
fundamental operations: push, pop and stack top
6. The basic operations that can be performed
on stack:
• Push: The process of adding a new element of
top of the stack is called push operation.
Pushing an element In the stack invoke adding
of element, as the new element will be inserted
at the top after every push operation the top is
incremented by one. In case the array is full and
no new element can be accommodated ,it is
called stack full condition . This condition is
called stack overflow.
7. Pop: the process of deleting an element from the
Top of the stack is called pop operation. After
every pop operation the stack is decrement by
one. If there is no element on the stack and the
pop is performed then this will result into stack
underflow condition.
8. • A common model of a stack is plates in a
marriage party or coin stacker. Fresh plate are
“pushed” onto to the top and “popped ” from the
top.
9. Stack implementation
Stacks
static array dynamic arrays
Graphical region
Parenthesis
fill
checker
10. Stack implementation in two way:
• Static implementation: these implementation uses
arrays to create stack. Static implementation
though a very simple technique but is not a
flexible way of creation as the size of stack has
to be declared during program design after that
can not be varied. Static implementation is not
too efficient with respect to memory utilization.
• Dynamic implementation: these implementation is
also called link list implementation and uses
pointer to implement the stack type of data
structure.
11. Stack Applications
• A Palindrome is a string that reads the same
in either direction
– Examples: “Able was I ere I saw Elba”
• Reversing the string
• Implementation of DFS
- a stack is the proper data structure to
remember the current node and how to
backtrack.
12. Calculation of arithmetic notation
• Infix notation: the infix notetion is what we come
across our general mathematics, where the
opereter is written in between the operand.
Example: A+B
• prefix notation: the prefix notation a notation in which
the operators is written before the operand, it is also
called polish notation.
Example: +AB
• Postfix notation: in the postfix notation the operators
are written after the operands, so it’s called the postfix
notation’ it’s also called suffix notation.
Example :AB+
