Lexical Analyzer Project

Project Description This project is a simple lexical analyzer written in Java. It reads a source code file, analyzes each line, and classifies the contents into various types of tokens such as keywords, identifiers, numbers, operators, delimiters, comments, and errors.

How It Works The analyzer uses regular expressions (regex) to recognize and classify tokens into the following types:

Token Type	Description
KEYWORD	Reserved keywords such as start, finish, if, etc.
IDENTIFIER	Variable names that start with a letter and can have up to 8 alphanumeric characters
NUMBER	Integer numbers with up to 8 digits
OPERATOR	Operators such as ==, !=, +, -, *, /, %, etc.
DELIMITER	Symbols like ;, {}, (), ,, .
COMMENT	Lines starting with //
WHITESPACE	Spaces, tabs, or new lines (ignored by the analyzer)
ERROR	Any invalid or unrecognized token

📂 File Structure LexicalAnalyzer.java -> Main source file for the analyzer program.txt -> Input file containing source code to analyze

How to Use

1. Add your code to program.txt.
2. Compile and run LexicalAnalyzer.java.
3. The output will display all recognized tokens and any errors found.

Example Output Token: start, Class: KEYWORD Token: var, Class: KEYWORD Token: x, Class: IDENTIFIER Token: =, Class: OPERATOR Token: 123456789, Class: ERROR Error: Number '123456789' exceeds the allowed 8 digits. Token: // this is a comment, Class: COMMENT

Requirements

• Java JDK 8 or higher
• A text editor or Java IDE (e.g., IntelliJ IDEA, Eclipse, VS Code)
• Make sure the program.txt file is in the same directory as the .java file

🧾 Notes

• Whitespace is ignored and not printed in the output.
• Numbers longer than 8 digits are flagged as errors.
• You can customize the patterns in the code to support more language features.