Role of Automata in Lexical analysis

Lexical analysis is a process of recognizing the input source program. To recognize tokens lexical analyzers perform following steps-

1. Lexical analyzers store the input in input in the input buffer.
2. The token is read from the input buffer and regular expressions are built for the corresponding token.
3. From these regular expressions, finite automata are built. The finite automata are usually in the non-deterministic form. That means Non-deterministic. Finite Automata (NFA) is built.
4. For each state of NFA, a function is designed and each input along the transitional edges corresponds to input parameters of these functions.
5. The set of such functions ultimately creates a lexical analyzer program.

As Finite Machine (FDM( or finite Automata play a very important role in design of lexical analyzer we will first understand the concept of finite automata......