Add Command-Line Tic-Tac-Toe Game with Two-Player Support

[tomcat323]

Description

This PR implements a fully functional command-line tic-tac-toe game that allows two players to play against each other. The game provides an interactive experience with clear instructions and proper game state management.

Features Implemented

Core Game Mechanics

• Two-Player Support: Players take turns as X and O
• 3x3 Grid Display: Visual board representation that updates after each move
• Move Input: Players specify positions (1-9) to place their marks
• Move Validation: Ensures moves are only made to empty positions
• Win Detection: Checks for three-in-a-row horizontally, vertically, and diagonally
• Draw Detection: Identifies when the board is full with no winner

User Experience

• Clear instructions for players at game start
• Visual board updates after each move
• Input validation with error messages for invalid moves
• Game result announcement (winner or draw)
• Command-line executable script

Technical Details

Implementation

• Language: Python
• File: tic_tac_toe.py
• Executable: Script is marked as executable for direct command-line use
• Board Representation: Uses a list-based data structure for efficient game state management
• Win Patterns: Implements all 8 possible winning combinations (3 horizontal, 3 vertical, 2 diagonal)

Additional Changes

• Added .gitignore file to exclude Python build artifacts and IDE/OS specific files

How to Use

Run the game from the command line:

python tic_tac_toe.py

Or if executable permissions are set:

./tic_tac_toe.py

Players will be prompted to enter positions (1-9) corresponding to the board layout:

1 | 2 | 3
---------
4 | 5 | 6
---------
7 | 8 | 9

Testing Considerations

The implementation includes:

• Input validation for move positions
• Boundary checking for board positions
• Win condition verification for all possible winning patterns
• Draw condition detection when board is full

Requirements Met

✅ Command-line tic-tac-toe game script created
✅ Two-player gameplay support
✅ 3x3 grid display with current board state
✅ Turn-based move input system
✅ Move validation for empty positions only
✅ Win condition checking (horizontal, vertical, diagonal)
✅ Draw condition detection
✅ Game result display
✅ Clear player instructions
✅ Command-line executable