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 Yellow */
#define BOLDWHITE   "\033[1m\033[37m"      /* Bold White */
#define BOLDMAGENTA "\033[1m\033[35m"      /* Bold Magenta */
#define RESET       "\033[0m"

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

    //this could be tidier i think
    if(players == 1){
        do{
            flag = check_win();
            if(free_spaces() == 0){
                break;
            }

            print_board();

            player_choice('X');
            print_board();

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

        } while(flag == ' ');

    } else if(players == 2){
            do{
                flag = check_win();
                if(free_spaces() == 0){
                    break;
                }

                print_board();

                player_choice('X');
                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(2);
    } 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;
}