TicTacToe.c

/*
  This game is for Unix only.
  
  It is a simple yet easily navigable Tic-Tac-Toe game for the Unix terminal. To run this file, go
  to your awesome Unix terminal and (after you have downloaded this text file, of course) and
  navigate to this file. Then, compile and link the program with your handy compiler which will
  almost definitely be installed unless you have removed it using the command 'gcc TicTacToe.c'.
  This creates an executeable. To run it, you can simply type './a.out'. If you want to have a more
  memorable file and/or prevent conflicts, simply change the name with the 'mv' tool
  ('mv a.out TicTacToe') or use the '-o' ("output file") when compiling
  ('gcc TicTacToe.c -o TicTacToe').
  
  This game, although not a particularly fun game, shows how to use key strokes rather than
  waiting for the Enter key. One can, therefore, press 'j', Space or any key and have it register
  immediately. Hopefully it can be of use.
*/

#include <stdio.h>
#include <unistd.h> /* for STDIN_FILENO */
#include <termios.h>

void printBoard(void);

// globals
char keys[] = {0, 0, 0, 0};  // the keys entered 
/*  (remember: some keys produce multiple characters;
    i.e. left = \x1b [ D (3 chars)
*/
int curpos = 0;             // position of the cursor
int i;                      // helper
int p;                      // position for printing board in loop
char board[] = {            // board
                ' ', ' ', ' ', 
                ' ', ' ', ' ', 
                ' ', ' ', ' ', };
int turn = 0;              // (turn % 2 == 0) = X; (turn % 2 == 1) = O
char winner;

struct termios old, t;


int main() {
    tcgetattr(STDIN_FILENO, &old);
    t = old;

    // format Unix terminal (reset, move to (0,0), clear to bottom, change title to "Tic-Tac-Toe", turn off cursor (prevents flickering and looks better)
    printf("\x1bc\x1b[0;0H\x1b[J\x1b]0;Tic-Tac-Toe\x07\x1b[?25l");

    printBoard();

    char ch = 0;
    while (keys[0] != 'q') {
        keys[3] = keys[2];
        keys[2] = keys[1];
        keys[1] = keys[0];
        cfmakeraw(&t);
        tcsetattr(STDIN_FILENO, TCSANOW, &t);
        keys[0] = getc(stdin);
        tcsetattr(STDIN_FILENO, TCSANOW, &old);

        // UP
        if (keys[2] == 27 && keys[1] == 91 && keys[0] == 65) {
            // cursor curpos on first row (move to last)
            if (curpos / 3 == 0) {
                curpos += 2 * 3;
            } else {
                curpos -= 3;
            }
        // DOWN
        } else if (keys[2] == 27 && keys[1] == 91 && keys[0] == 66) {
            // cursor curpos on last row (move to first)
            if (curpos / 3 == 2) {
                curpos -= 2 * 3;
            } else {
                curpos += 3;
            }
        // RIGHT
        } else if (keys[2] == 27 && keys[1] == 91 && keys[0] == 67) {
            // cursor curpos on right-most column (move to left-most)
            if (curpos % 3 == 2) {
                curpos -= 2;
            } else {
                curpos += 1;
            }
        // LEFT
        } else if (keys[2] == 27 && keys[1] == 91 && keys[0] == 68) {
            // cursor curpos on left-most column (move to right-most)
            if (curpos % 3 == 0) {
                curpos += 2;
            } else {
                curpos -= 1;
            }
        // ENTER or SPACE
        } else if (keys[0] == 13 || keys[0] == 32) {
            if (board[curpos] == ' ') {
                if (turn % 2 == 0) {
                    board[curpos] = 'X';
                } else {
                    board[curpos] = 'O';
                }
                turn++;
            }
        }
        // temporary... print key pressed
        //printf("\n %d %d %d %d", keys[0], keys[1], keys[2], keys[3]);

        printBoard();

        // check for winner
        // ----------------
        if (board[0] == 'X' && board[1] == 'X' && board[2] == 'X' || // row 1
           board[3] == 'X' && board[4] == 'X' && board[5] == 'X' ||  // row 2
           board[6] == 'X' && board[7] == 'X' && board[8] == 'X' ||  // row 3
           board[0] == 'X' && board[3] == 'X' && board[6] == 'X' ||  // col 1
           board[1] == 'X' && board[4] == 'X' && board[7] == 'X' ||  // col 2
           board[2] == 'X' && board[5] == 'X' && board[8] == 'X' ||  // col 3
           board[0] == 'X' && board[4] == 'X' && board[8] == 'X' ||  // diag top-left to bottom-right
           board[2] == 'X' && board[4] == 'X' && board[6] == 'X') {  // diag top-right to bottom-left
            printf("\n\n\x1b[34;1mX\x1b[m wins!           [enter]");
            getchar();
            printf("\x1b[0;0H\x1b[J");
            for (i = 0; i < 9; i++) {
                board[i] = ' ';
            }
            turn = 0;
            printBoard();
        }
        if (board[0] == 'O' && board[1] == 'O' && board[2] == 'O' || // row 1
           board[3] == 'O' && board[4] == 'O' && board[5] == 'O' ||  // row 2
           board[6] == 'O' && board[7] == 'O' && board[8] == 'O' ||  // row 3
           board[0] == 'O' && board[3] == 'O' && board[6] == 'O' ||  // col 1
           board[1] == 'O' && board[4] == 'O' && board[7] == 'O' ||  // col 2
           board[2] == 'O' && board[5] == 'O' && board[8] == 'O' ||  // col 3
           board[0] == 'O' && board[4] == 'O' && board[8] == 'O' ||  // diag top-left to bottom-right
           board[2] == 'O' && board[4] == 'O' && board[6] == 'O') {  // diag top-right to bottom-left
            printf("\n\n\x1b[33;1mO\x1b[m wins!           [enter]");
            getchar();
            printf("\x1b[0;0H\x1b[J");
            for (i = 0; i < 9; i++) {
                board[i] = ' ';
            }
            turn = 0;
            printBoard();
        }
        
        // check for tie
        if (turn == 9) {
            printf("\n\nIt's a tie!          [Enter]");
            getchar();
            printf("\x1b[0;0H\x1b[J");
            for (i = 0; i < 9; i++) {
                board[i] = ' ';
            }
            turn = 0;
            printBoard();

        }
    }
        
    printf("\x1b[?25h");
    return 0;
}

void printBoard(void) {
    printf("\x1b[0;0Hpress 'q' to quit\n\n", curpos % 3 + 1, curpos / 3 + 1);
    for (p = 0; p < 9; p++) {
        printf("|");

        if (p == curpos) {
            printf("\x1b[7m"); // turn on rev. color (if cursor on this pos)
        }

        if (board[p] == 'X') {
            printf("\x1b[34;1m");
        } else if (board[p] == 'O') {
            printf("\x1b[33;1m");
        }

        putchar(board[p]);

        if (board[p] == 'X' || board[p] == 'O') {
            printf("\x1b[m");
        }

        if (p == curpos) {
            printf("\x1b[27m"); // turn off rev. color (if cursor on this pos)
        }

        if (p % 3 == 2) {
            printf("|\n");
        }
    }
}