#include <stdio.h>
/*
A simple Tic‑Tac‑Toe game written in C.
Highlights:
- The board is represented as a 1D array of 9 chars.
- 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
void printBoard(const char board[9]) {
printf("\n");
for (int i = 0; i < 9; i++) {
printf("%c", board[i]);
if ((i + 1) % 3 == 0)
printf("\n");
else
printf(" | ");
}
printf("\n");
}
// Check if a player has won
int checkWin(const char board[9], char player) {
// All winning combinations
int wins[8][3] = {
{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
};
for (int i = 0; i < 8; i++) {
int a = wins[i][0];
int b = wins[i][1];
int c = wins[i][2];
if (board[a] == player &&
board[b] == player &&
board[c] == player)
return 1;
}
return 0;
}
// Check if the board is full (draw)
int boardFull(const char board[9]) {
for (int i = 0; i < 9; i++) {
if (board[i] == ' ')
return 0;
}
return 1;
}
// Attempt to place a move; return 1 if successful
int placeMove(char board[9], int pos, char player) {
if (pos < 0 || pos >= 9)
return 0;
if (board[pos] != ' ')
return 0;
board[pos] = player;
return 1;
}
int main() {
char board[9];
// Initialize board with spaces
for (int i = 0; i < 9; i++)
board[i] = ' ';
char currentPlayer = 'X';
printf("Tic‑Tac‑Toe\n");
printBoard(board);
while (1) {
printf("Player %c, enter position (0‑8): ", currentPlayer);
int pos;
scanf("%d", &pos);
// Try to place the move
if (!placeMove(board, pos, currentPlayer)) {
printf("Invalid move. Try again.\n");
continue;
}
printBoard(board);
// Check win
if (checkWin(board, currentPlayer)) {
printf("Player %c wins!\n", currentPlayer);
break;
}
// Check draw
if (boardFull(board)) {
printf("It's a draw!\n");
break;
}
// Switch player
currentPlayer = (currentPlayer == 'X') ? 'O' : 'X';
}
return 0;
}
/*
run: 1
Tic‑Tac‑Toe
| |
| |
| |
Player X, enter position (0‑8): 0
X | |
| |
| |
Player O, enter position (0‑8): 4
X | |
| O |
| |
Player X, enter position (0‑8): 8
X | |
| O |
| | X
Player O, enter position (0‑8): 7
X | |
| O |
| O | X
Player X, enter position (0‑8): 1
X | X |
| O |
| O | X
Player O, enter position (0‑8): 2
X | X | O
| O |
| O | X
Player X, enter position (0‑8): 6
X | X | O
| O |
X | O | X
Player O, enter position (0‑8): 3
X | X | O
O | O |
X | O | X
Player X, enter position (0‑8): 5
X | X | O
O | O | X
X | O | X
It's a draw!
*/
/*
run: 2
Tic‑Tac‑Toe
| |
| |
| |
Player X, enter position (0‑8): 9
Invalid move. Try again.
Player X, enter position (0‑8): 0
X | |
| |
| |
Player O, enter position (0‑8): 1
X | O |
| |
| |
Player X, enter position (0‑8): 0
Invalid move. Try again.
Player X, enter position (0‑8): 8
X | O |
| |
| | X
Player O, enter position (0‑8): 6
X | O |
| |
O | | X
Player X, enter position (0‑8): 4
X | O |
| X |
O | | X
Player X wins!
*/
