Introduction
Converting a regular expression to a finite automaton means turning a pattern description into a step-by-step machine that checks if a string fits that pattern. It's like creating a specialized robot that follows the rules of the pattern to see if a string matches.
Regular Expressions are the expressions that describe the language accepted by Finite Automata. It is the most efficient way to represent any language.
We can easily convert the Regular expressions (also check out some examples of regular expressions)to Finite automata.
Let’s understand the steps required to convert the Regular expressions to Finite automata.
Also See, Moore Machine
Steps To Convert Regular Expressions To Finite Automata
To convert the RE to FA, the method that is popularly used is known as the Subset method. This method is used to get FA from the given regular expression.
The steps in this method are given below:-
Step 1: Make a transition diagram for a given regular expression, using NFA with ε moves.
Step 2: Then, Convert this NFA with ε to NFA without ε.
Step 3: Finally, Convert the obtained NFA to equivalent DFA.
Some standard rules help in the conversion of RE to NFA are:-
1.) If RE is in the form a+b, it can be represented as:
2.) If RE is in the form ab, it can be represented as:
3.) If RE is in the form of a*, it can be represented as:
In the next section, we will implement the above method to convert the RE to FA.
Also read - arden's theorem
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