Build Your First Python Game - Tic Tac Toe

# 🔧 Mini-Challenge 1: Create and Explore the Board

# Create an empty board (9 empty spaces)
board = [" "] * 9

print("Our empty board list:")
print(board)
print()

# Let's see what's at different positions
print("Position 0 (top-left):", repr(board[0]))
print("Position 4 (center):", repr(board[4]))  
print("Position 8 (bottom-right):", repr(board[8]))
print()

# Now let's place some symbols and see what happens
board[0] = "X"  # Top-left
board[4] = "O"  # Center  
board[8] = "X"  # Bottom-right

print("After placing some symbols:")
print(board)

# 🔧 Mini-Challenge 2: Build the Display Pattern

# Let's start with a board that has some moves
board = [" ", " ", "X", " ", "O", " ", " ", " ", "X"]

print("Current board list:", board)
print()
print("Let's display it as a tic-tac-toe board:")
print()

# First, let's just print the positions manually to understand the pattern
print("Row 1 - positions 0, 1, 2:")
print(f" {board[0]} | {board[1]} | {board[2]}")

print("Separator:")
print("---+---+---")

print("Row 2 - positions 3, 4, 5:")  
print(f" {board[3]} | {board[4]} | {board[5]}")

print("Separator:")
print("---+---+---")

print("Row 3 - positions 6, 7, 8:")
print(f" {board[6]} | {board[7]} | {board[8]}")

# 🔧 Mini-Challenge 3: Create Your First Function

def print_board(board):
    """This function takes a board list and displays it as tic-tac-toe"""
    print()  # Empty line for spacing
    print(f" {board[0]} | {board[1]} | {board[2]}")
    print("---+---+---")
    print(f" {board[3]} | {board[4]} | {board[5]}")
    print("---+---+---")
    print(f" {board[6]} | {board[7]} | {board[8]}")
    print()  # Empty line for spacing

# Test it out!
test_board = ["X", " ", "O", " ", "X", " ", "O", " ", " "]
print("Testing our function:")
print_board(test_board)

# Try with a different board
another_board = [" "] * 9  # Empty board
print("Empty board:")
print_board(another_board)

# 🔧 Mini-Challenge 4: Understanding Input

# Let's see what happens with basic input
player_input = input("Enter a position (1-9): ")

print(f"You entered: '{player_input}'")
print(f"Type of input: {type(player_input)}")

# Try to use it as a number
try:
    position = int(player_input)
    print(f"As a number: {position}")
    
    # Convert to list index (subtract 1)
    list_index = position - 1
    print(f"List index: {list_index}")
    
except ValueError:
    print("Oops! That's not a number!")

# 🔧 Mini-Challenge 5: Build Input Validation

def get_valid_input():
    """Get a valid position (1-9) from the player"""
    while True:  # Keep asking until we get valid input
        player_input = input("Enter your move (1-9): ")
        
        # Check if it's a number
        if not player_input.isdigit():
            print("Invalid input! Please enter a number.")
            continue  # Go back to start of loop
            
        # Convert to integer
        position = int(player_input)
        
        # Check if it's in the right range
        if position < 1 or position > 9:
            print("Invalid position! Choose a number between 1 and 9.")
            continue  # Go back to start of loop
            
        # If we get here, the input is valid!
        return position - 1  # Convert to list index (0-8)

# Test it!
print("Testing input validation:")
print("Try entering invalid inputs to see what happens!")
valid_index = get_valid_input()
print(f"Great! You chose list index: {valid_index}")

# 🔧 Mini-Challenge 6: Handle Move Placement

def make_move(board, position, player):
    """Try to place a player's symbol at the given position"""
    if board[position] != " ":
        print("That spot is already taken! Try again.")
        return False  # Move failed
    else:
        board[position] = player
        return True   # Move succeeded

# Test it!
test_board = [" "] * 9
print("Starting with empty board:")
print_board(test_board)

# Try to place X at position 4 (center, list index 4)
print("Player X chooses center (position 5):")
success = make_move(test_board, 4, "X")
if success:
    print_board(test_board)

# Try to place O in the same spot
print("Player O also tries center:")
success = make_move(test_board, 4, "O")
if success:
    print_board(test_board)
else:
    print("Move was blocked!")

# 🔧 Mini-Challenge 7: Build Win Detection

def check_winner(board, player):
    """Check if the given player has won"""
    # All possible winning combinations (as list indices)
    win_combinations = [
        [0, 1, 2],  # Top row
        [3, 4, 5],  # Middle row
        [6, 7, 8],  # Bottom row
        [0, 3, 6],  # Left column
        [1, 4, 7],  # Middle column
        [2, 5, 8],  # Right column
        [0, 4, 8],  # Top-left to bottom-right diagonal
        [2, 4, 6]   # Top-right to bottom-left diagonal
    ]
    
    # Check each winning combination
    for combo in win_combinations:
        if (board[combo[0]] == player and 
            board[combo[1]] == player and 
            board[combo[2]] == player):
            return True
    
    return False

# Test it!
# Create a winning board for X
winning_board = ["X", "X", "X", " ", "O", " ", " ", "O", " "]
print("Test board:")
print_board(winning_board)

print("Does X win?", check_winner(winning_board, "X"))
print("Does O win?", check_winner(winning_board, "O"))

# 🔧 Mini-Challenge 8: Detect Ties

def is_tie(board):
    """Check if the board is full (tie game)"""
    return " " not in board

# Test it!
full_board = ["X", "O", "X", "O", "X", "O", "O", "X", "O"]
print("Full board:")
print_board(full_board)
print("Is it a tie?", is_tie(full_board))

partial_board = ["X", "O", " ", "O", "X", " ", " ", " ", " "]
print("\nPartial board:")
print_board(partial_board)
print("Is it a tie?", is_tie(partial_board))

# 🎮 The Complete Game!

def play_game():
    """Run a complete game of tic-tac-toe"""
    # Initialize the game
    board = [" "] * 9
    current_player = "X"
    
    print("🎮 Welcome to Tic-Tac-Toe!")
    print("Players take turns choosing a position (1–9).")
    print()
    
    # Show reference board
    reference = ["1", "2", "3", "4", "5", "6", "7", "8", "9"]
    print("Board positions:")
    print_board(reference)
    
    # Main game loop
    while True:
        print(f"Current board:")
        print_board(board)
        
        # Get valid input
        print(f"Player {current_player}'s turn!")
        position = get_valid_input()
        
        # Try to make the move
        if make_move(board, position, current_player):
            # Move successful - check for win/tie
            if check_winner(board, current_player):
                print_board(board)
                print(f"🎉 Player {current_player} wins!")
                break
                
            if is_tie(board):
                print_board(board)
                print("🤝 It's a tie!")
                break
                
            # Switch players
            current_player = "O" if current_player == "X" else "X"
        
        # If move failed, player tries again (don't switch players)

# Run the game!
if __name__ == "__main__":
    play_game()