Tic Tac Toe CLI Game 🕹️

A command-line Tic Tac Toe (noughts and crosses) game in Python with artificial intelligence at three difficulty levels.

🎯 Features

• Game mode: Human player vs AI
• Three difficulty levels:
  • Easy: Random moves
  • Medium: Blocks player's threats
  • Hard: Minimax algorithm for perfect play
• CLI Interface: Clean and intuitive terminal
• Input validation: Robust error handling
• Replayability: Ability to play multiple games

🚀 Installation

Prerequisites

• Python 3.6+
• Git (optional)

Quick Installation

# Clone the repository
git clone <repository-url>
cd tic-tac-toe

# Create virtual environment
python3 -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

# Install dependencies (none for base version)
pip install -r requirements.txt

# Launch the game
python main.py

🎮 How to Play

1. Launch the game: python main.py
2. Choose difficulty: 1 (Easy), 2 (Medium), 3 (Hard)
3. Make your move: Enter coordinates in row,column format (ex: 0,1)
4. You are X, AI is O
5. Replay: Choose to replay after each game

🧪 Tests

# Unit tests
python -m unittest tests.test_board tests.test_ai

# Quick validation test
python test_game.py

📁 Project Structure

tic-tac-toe/
├── main.py                 # Main entry point
├── test_game.py           # Quick validation tests
├── requirements.txt       # Python dependencies
├── README.md              # Documentation
├── MEMO/                  # Development documentation
│   ├── context.md         # Context and objectives
│   ├── decisions.md       # Technical decisions
│   ├── errors_log.md      # Error history
│   └── progress.md        # Progress status
├── src/                   # Source code
│   ├── __init__.py        # Python package
│   ├── board.py           # Game board management
│   ├── ai.py              # Artificial intelligence
│   └── game.py            # Main game logic
├── tests/                 # Unit tests
│   ├── test_board.py      # Board tests
│   └── test_ai.py         # AI tests
└── docs/                  # Technical documentation

🏗️ Architecture

Main Classes

• Board: 3x3 board state management

  • Move validation
  • Win detection
  • Board display

• AI: Artificial intelligence with three levels

  • Easy: random.choice() on empty cells
  • Medium: Winning/blocking move search
  • Hard: Minimax algorithm with alpha-beta pruning

• TicTacToeGame: Game orchestrator

  • Turn management
  • CLI user interface
  • Main game loop

Hard AI Algorithm

The hard AI uses the Minimax algorithm with optimization:

• Maximum depth: 9 (complete board)
• Scores: +10 (AI win), -10 (player win), 0 (draw)
• Optimization: Preference for quick wins

🎯 Quality Metrics

• Test coverage: > 80%
• Cyclomatic complexity: < 10 per function
• AI response time: < 50ms (hard)
• Code size: < 500 lines total

🤝 Contributing

1. Fork the project
2. Create a feature branch (git checkout -b feature/AmazingFeature)
3. Commit changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

🙏 Acknowledgments

• Inspired by classic Tic Tac Toe games
• Developed with TDD (Test-Driven Development) approach
• Modular architecture for easy extension

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🎉 Have fun!