#
# A simple Tic‑Tac‑Toe game written in Ruby.
#
# Highlights:
# - The board is represented as an Array of 9 characters.
# - Functions handle printing, move validation, win checking,
# and turn progression.
# - The game loop is clear and easy to follow.
# - Comments explain the reasoning behind each part of the program.
#
#---------------------------------------------------------------
# Print the board in a 3×3 layout
#---------------------------------------------------------------
def print_board(board)
puts
board.each_with_index do |cell, i|
print cell
if (i + 1) % 3 == 0
puts
else
print " | "
end
end
puts
end
#---------------------------------------------------------------
# Check if a player has won
#---------------------------------------------------------------
def check_win(board, player)
wins = [
[0,1,2], [3,4,5], [6,7,8], # rows
[0,3,6], [1,4,7], [2,5,8], # columns
[0,4,8], [2,4,6] # diagonals
]
wins.any? { |a, b, c| board[a] == player && board[b] == player && board[c] == player }
end
#---------------------------------------------------------------
# Check if the board is full (draw)
#---------------------------------------------------------------
def board_full(board)
board.none? { |c| c == " " }
end
#---------------------------------------------------------------
# Attempt to place a move; return true if successful
#---------------------------------------------------------------
def place_move(board, pos, player)
return false unless pos.between?(0, 8)
return false unless board[pos] == " "
board[pos] = player
true
end
#---------------------------------------------------------------
# Main game loop
#---------------------------------------------------------------
board = Array.new(9, " ")
current_player = "X"
puts "Tic‑Tac‑Toe"
print_board(board)
loop do
print "Player #{current_player}, enter position (0‑8): "
input = gets&.strip
unless input =~ /^\d+$/
puts "Invalid input. Try again."
next
end
pos = input.to_i
unless place_move(board, pos, current_player)
puts "Invalid move. Try again."
next
end
print_board(board)
if check_win(board, current_player)
puts "Player #{current_player} wins!"
break
end
if board_full(board)
puts "It's a draw!"
break
end
current_player = current_player == "X" ? "O" : "X"
end
__END__
=begin
run:
Tic‑Tac‑Toe
| |
| |
| |
Player X, enter position (0‑8): 3
| |
X | |
| |
Player O, enter position (0‑8): 5
| |
X | | O
| |
Player X, enter position (0‑8): 8
| |
X | | O
| | X
Player O, enter position (0‑8): 1
| O |
X | | O
| | X
Player X, enter position (0‑8): 0
X | O |
X | | O
| | X
Player O, enter position (0‑8): 7
X | O |
X | | O
| O | X
Player X, enter position (0‑8): 6
X | O |
X | | O
X | O | X
Player X wins!
=end
