DFA to Regular Expression Converter

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This C++ project converts a Deterministic Finite Automaton (DFA) into its equivalent Regular Expression (Regex) using the state elimination method.

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📌 Features

• Interactive CLI to input DFA components
• Automatically adds start and final dummy states for proper elimination
• Handles ε (epsilon) transitions
• Supports multiple final states
• Merges multiple transitions between the same states
• Handles and ignores dummy (dead/unreachable) states gracefully
• Simplifies unnecessary parentheses in the final expression

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🚀 How It Works

1. User Input:

   • States
   • Start State
   • Final States
   • Transition Symbols
   • Transitions

2. Processing:

   • Adds virtual Start (Start0) and Final (Final0) states
   • Merges transitions between same source and destination
   • Eliminates intermediate states via the state elimination method
   • Generates a Regular Expression using path combinations
   • Simplifies excess brackets in the final expression

3. Output:

   • Transition Table
   • Final Regular Expression

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🧪 Sample DFA Input

States: 1 2 3 -1
Start State: 1
Final States: 2 3 -1
Symbols: a b -1

Transitions:
For state '1': a -> 2, b -> 3
For state '2': a -> 3, b -> 2
For state '3': a -> 2, b -> 3

✅ Output:

The Regular Expression is: a(b)*U(b(bUa(b)a))

🛠️ How to Compile & Run

g++ -o dfa_to_regex dfa_to_regex.cpp
./dfa_to_regex

🧠 Important Notes

To stop entering states, final states, or symbols, type -1.

Epsilon (ε) transitions are represented as "E" internally.

Redundant outer parentheses are removed for cleaner output.

🧳 Future Improvements

i. GUI support for DFA input

ii. Visual representation of transitions

iii. Support for NFA and Epsilon-NFA to Regex conversion

👨‍💻 Author

cgcb-01 🔗 https://github.com/cgcb-01

📄 License

This project is licensed under the MIT License.