c-tictactoe/main.c

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>

#define ROWS 3
#define COLUMNS 3
#define RED "\033[31m"                /* Red */
#define BOLDGREEN "\033[1m\033[32m"   /* Bold Green */
#define BOLDYELLOW "\033[1m\033[33m"  /* Bold Yellow */
#define BOLDRED "\033[1m\033[31m"     /* Bold RED */
#define BOLDWHITE "\033[1m\033[37m"   /* Bold White */
#define BOLDMAGENTA "\033[1m\033[35m" /* Bold Magenta */
#define RESET "\033[0m"               /* Reset colour */

char board[ROWS][COLUMNS];

void print_board();
void clear_board();
void player_choice(char player);
void cpu_choice(char cpu);
char check_win();
int free_spaces();

int main(int argc, char *argv[]) {
  char flag = ' ';
  int players;
  unsigned int sleeptime = 1; // seconds to sleep
  clear_board();

  printf("How many players? (1/2)\n> ");
  scanf("%d", &players); // something better than scanf("%d")

  // TODO Tidy this up!
  switch (players) {
  case 1:
    do {
      flag = check_win();
      if (free_spaces() == 0) {
        break;
      }

      print_board();

      player_choice('X');
      flag = check_win();
      print_board();
      sleep(sleeptime);

      cpu_choice('O');
      flag = check_win();
      print_board();
      sleep(sleeptime);

    } while (flag == ' ');

  case 2:
    do {
      flag = check_win();
      if (free_spaces() == 0) {
        break;
      }

      print_board();

      player_choice('X');
      flag = check_win();
      print_board();

      player_choice('O');
      flag = check_win();
      print_board();

    } while (flag == ' ');
  }
  if (flag == ' ')
    printf(BOLDMAGENTA "\nNo-one won!" RESET);
  else
    printf(BOLDMAGENTA "\n%c won!" RESET, flag);

  printf(BOLDWHITE "\nGame Over!\n" RESET);
  return 0;
}

void print_board() {
  system("clear");
  printf(BOLDWHITE "  1   2   3 \n" RESET);

  printf(BOLDWHITE "1 " RESET);
  printf("%c | %c | %c ", board[0][0], board[0][1], board[0][2]);
  printf("\n ---|---|---\n");

  printf(BOLDWHITE "2 " RESET);
  printf("%c | %c | %c ", board[1][0], board[1][1], board[1][2]);
  printf("\n ---|---|---\n");

  printf(BOLDWHITE "3 " RESET);
  printf("%c | %c | %c ", board[2][0], board[2][1], board[2][2]);

  printf("\n");
}

void clear_board() {
  int r, c;
  for (r = 0; r < ROWS; ++r) {
    for (c = 0; c < COLUMNS; ++c) {
      board[r][c] = ' ';
    }
  }
}

int free_spaces() {
  int r, c, s;
  s = 0;
  for (r = 0; r < ROWS; ++r) {
    for (c = 0; c < COLUMNS; ++c) {
      if (board[r][c] == ' ')
        ++s;
    }
  }
  return s;
}

void player_choice(char player) {

  int pr, pc;
  printf(BOLDGREEN "\n[%c] Enter row (1, 2 or 3) <---->\n> " RESET, player);
  scanf("%d", &pr);
  --pr;

  printf(BOLDYELLOW "\n[%c] Enter column (1, 2 or 3) ^ v\n> " RESET, player);
  scanf("%d", &pc);
  --pc;

  if (board[pr][pc] != ' ') {
    printf(BOLDRED "\n[%c] Cannot play here, skipping...\n" RESET, player);
    sleep(1);
  } else {
    board[pr][pc] = player;
  }
}

void cpu_choice(char cpu) {
  time_t t;
  srand((unsigned)time(&t));

  int cr, cc;
  cr = cc = 0;
  while (board[cr][cc] != ' ') {
    cr = rand() % 3;
    cc = rand() % 3;
  }
  board[cr][cc] = cpu;
}

char check_win() {
  char flag = ' ';
  /*
  00 |01 |02
  ---|---|---
  10 |11 |12
  ---|---|---
  20 |21 |22
  */
  // horizontal checks l to r
  if (board[0][0] == board[0][1] && board[0][1] == board[0][2]) {
    flag = board[0][0];
  }
  if (board[1][0] == board[1][1] && board[1][1] == board[1][2]) {
    flag = board[1][0];
  }
  if (board[2][0] == board[2][1] && board[2][1] == board[2][2]) {
    flag = board[2][0];
  }

  // horizontal check up n down
  if (board[0][0] == board[1][0] && board[1][0] == board[2][0]) {
    flag = board[0][0];
  }
  if (board[0][1] == board[1][1] && board[1][1] == board[2][1]) {
    flag = board[0][1];
  }
  if (board[0][2] == board[1][2] && board[1][2] == board[2][2]) {
    flag = board[0][2];
  }

  // diagonal checks
  if (board[0][0] == board[1][1] && board[1][1] == board[2][2]) {
    flag = board[0][0];
  }
  if (board[0][2] == board[1][1] && board[1][1] == board[2][0]) {
    flag = board[0][2];
  }

  return flag;
}