/*
A simple Tic‑Tac‑Toe game written in PHP (CLI).
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
//---------------------------------------------------------------
function printBoard(array $board): void {
echo "\n";
for ($i = 0; $i < 9; $i++) {
echo $board[$i];
if (($i + 1) % 3 === 0) {
echo "\n";
} else {
echo " | ";
}
}
echo "\n";
}
//---------------------------------------------------------------
// Check if a player has won
//---------------------------------------------------------------
function checkWin(array $board, string $player): bool {
$wins = [
[0,1,2], [3,4,5], [6,7,8], // rows
[0,3,6], [1,4,7], [2,5,8], // columns
[0,4,8], [2,4,6] // diagonals
];
foreach ($wins as $w) {
if ($board[$w[0]] === $player &&
$board[$w[1]] === $player &&
$board[$w[2]] === $player) {
return true;
}
}
return false;
}
//---------------------------------------------------------------
// Check if the board is full (draw)
//---------------------------------------------------------------
function boardFull(array $board): bool {
foreach ($board as $c) {
if ($c === ' ') {
return false;
}
}
return true;
}
//---------------------------------------------------------------
// Attempt to place a move; return true if successful
//---------------------------------------------------------------
function placeMove(array &$board, int $pos, string $player): bool {
if ($pos < 0 || $pos >= 9) {
return false;
}
if ($board[$pos] !== ' ') {
return false;
}
$board[$pos] = $player;
return true;
}
//---------------------------------------------------------------
// Main game loop
//---------------------------------------------------------------
$board = array_fill(0, 9, ' ');
$currentPlayer = 'X';
echo "Tic‑Tac‑Toe\n";
printBoard($board);
while (true) {
echo "Player $currentPlayer, enter position (0‑8): ";
$input = trim(fgets(STDIN));
if (!ctype_digit($input)) {
echo "Invalid input. Try again.\n";
continue;
}
$pos = (int)$input;
// Try to place the move
if (!placeMove($board, $pos, $currentPlayer)) {
echo "Invalid move. Try again.\n";
continue;
}
printBoard($board);
// Check win
if (checkWin($board, $currentPlayer)) {
echo "Player $currentPlayer wins!\n";
break;
}
// Check draw
if (boardFull($board)) {
echo "It's a draw!\n";
break;
}
// Switch player
$currentPlayer = ($currentPlayer === 'X') ? 'O' : 'X';
}
/*
run:
Tic‑Tac‑Toe
| |
| |
| |
Player X, enter position (0‑8): 0
X | |
| |
| |
Player O, enter position (0‑8): 3
X | |
O | |
| |
Player X, enter position (0‑8): 6
X | |
O | |
X | |
Player O, enter position (0‑8): 4
X | |
O | O |
X | |
Player X, enter position (0‑8): 5
X | |
O | O | X
X | |
Player O, enter position (0‑8): 8
X | |
O | O | X
X | | O
Player X, enter position (0‑8): 2
X | | X
O | O | X
X | | O
Player O, enter position (0‑8): 1
X | O | X
O | O | X
X | | O
Player X, enter position (0‑8): 7
X | O | X
O | O | X
X | X | O
It's a draw!
*/
