PUSH DOWN AUTOMATON

"Finite state machine" + "a stack"

Pushdown automata are computational models that can do more than a finite state machine, but less than a Turing machine.The feature that distinguishes it from Finite automata is the use of stack in PDA.There is no repetition in the PDA, we put it where we are in his place.

Definition of the pushdown automaton

Our formal notation for a pushdown automaton involves seven componenents.The specification of a PDA:
P = (Q,∑,Γ,δ,qo,Zo,F )

The components have the following meanings:

Q : Set of states
∑ : Input alphabet
Γ : Stack symbol
δ : Transition function
qo : Initial state
Zo : Start symbol
F : Set of final states

δ = ∑ x Γ -> Γ* : It makes it possible not to write anything in the stack.We will look at the situation, look at the incoming input, pop or push according to it.
A pushdown automaton has three components :

an input tape
a control unit
a stack

A stack does two operations :

Push
Pop

State Diagram

According to the current situation, the incoming input is checked.
The stack pop () is made and stack push () is made.
State changes may also occur.

PDA Implemantation

To explain my application; The entered text will be checked to see if the input is accepted by putting a character in the finite control unit.

SedaCaglar_pda application

I made an application that show the steps of PDA. On this link you can download the jar file on GitHub

Reference :

https://brilliant.org/wiki/pushdown-automata

This page contains the push and pop operations in stack step by step for Push Down Automata.

This page was made by Seda Çağlar.Thanks for visit.