against_computer.c

/**
 * @file against_computer.c
 * @author Ayomide Suara (aysuarex@gmail.com)
 * 
 * singleplayer - driver function for single player mode
 * computerMove - controls how computer plays
 * playerMove - set of instructions for player's input
 * resetBoard - function to reset the board after each round
 * printBoard - draws and prints the board
 * checkFreeSpaces - checks if there are free spaces on the board
 * checkWinner - function that defines how to win the game
 * printWinner - checks who the winner is, and prints the result
 * 
 * @date 2022-08-18
 * 
 */

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>
#include <sys/time.h>
#include <ctype.h>
#include "main.h"

char board[3][3];
char choice;
char player;
char comp;
int x, y;


void singlePlayer()
{
    char winner;
    int response;

    do
    {
        Sleep(1000);
        system("cls");
        printf("===============================\n"
        "Welcome to Single player Mode!\n");
        placeholder();
        printf("\n-----------------------------------------------\n");
        printf("Select X or O:\n\t\t==> ");
        scanf("%s", &choice);
    
        if (choice == 'x' || choice == 'X')
        {
            player = 'X';
            comp = 'O';
            printf("\nPlayer = X\nComputer = O\n");
            break;
        }
        else if (choice == 'o' || choice == 'O')
        {
            player = 'O';
            comp = 'X';
            printf("\nPlayer = O\nComputer = X\n");
            break;
        }
        else
        {
            printf("\nERROR! Invalid Input\n");
        }

    } while ((choice != 'X') && (choice != '0'));
    

    do
    {
        Sleep(1800);
        system("cls");
    
        placeholder();
        printf("\nYour turn! Where do you wish to play?(1-9): ");

        Sleep(500);
        system("cls");

        winner = ' ';
        response = ' ';
        resetBoard();

        while (winner == ' '  && checkFreeSpaces() != 0)
        {
            
            system("cls");
            printBoard();

            playerMove();
            //check for Winner everytime after player's turn
            winner = checkWinner();
            if (winner != ' ' || checkFreeSpaces() == 0) // ''
            //once there's a winner or once we run out of space on the board
                break;
            
            Sleep(1000);
            //system("cls");
            computerMove();
            //check again for Winner after computer's turn
            winner = checkWinner();
            if (winner != ' ' || checkFreeSpaces() == 0) //''
            //once there's a winner or once we run out of space on the board
                break;
        }

        printBoard();
        printWinner(winner);

        printf("\nDo you wish to play again? (Y/N): ");
        scanf("%s", &response);
        response = toupper(response);
        
    } while (response == 'Y');

    printf("\nGame Over!\n");
    Sleep(1200);
    system("cls");
    return;
}

void printBoard()
{
    printf("\t\t\t\t\t\t      |      |      \n");
    printf("\t\t\t\t\t\t   %c  |   %c  |  %c  \n", board[0][0], board[0][1], board[0][2]);
    printf("\t\t\t\t\t\t______|______|______\n");
    printf("\t\t\t\t\t\t      |      |      \n");
    printf("\t\t\t\t\t\t   %c  |   %c  |  %c  \n", board[1][0], board[1][1], board[1][2]);
    printf("\t\t\t\t\t\t______|______|______\n");
    printf("\t\t\t\t\t\t      |      |      \n");
    printf("\t\t\t\t\t\t   %c  |   %c  |  %c  \n", board[2][0], board[2][1], board[2][2]);
    printf("\t\t\t\t\t\t      |      |      \n");
    return;
}

void resetBoard() //makes all the spaces on the board empty
{
    for (int i=0; i<3; i++)
    {
        for (int j=0; j<3; j++)
        {
            board[i][j] = ' ';
        }
    }
    return;
}

int checkFreeSpaces()
{
    int freeSpaces = 9;

    for (int i=0; i<3; i++)
        for (int j=0; j<3; j++)
            if (board[i][j] != ' ')
            {
                freeSpaces--;
            }
    return freeSpaces;
}

void playerMove()
{
    do
    {
        Turn:
        printf("\nYour turn! Where do you wish to play?(1-9): ");
        scanf("%s", &choice);

        if (choice == '1')
        {
            x = 0;
            y = 0;    
        }
        else if (choice == '2')
        {
            x = 0;
            y = 1;
        }
        else if (choice == '3')
        {
            x = 0;
            y = 2;
        }
        else if (choice == '4')
        {
            x = 1;
            y = 0;
        }
        else if (choice == '5')
        {
            x = 1;
            y = 1;
        }
        else if (choice == '6')
        {
            x = 1;
            y = 2;
        }
        else if (choice == '7')
        {
            x = 2;
            y = 0;
        }
        else if (choice == '8')
        {
            x = 2;
            y = 1;
        }
        else if (choice == '9')
        {
            x = 2;
            y = 2;
        }
        else
        {
            printf("ERROR! Invalid Option\n");
            goto Turn;
        }

        if (board[x][y] != ' ')
        {
            printf("ERROR! Occupied\n");
            goto Turn;
        }
        else
        {
            board[x][y] = player; 
            //if the position is free, put the player's token there
            break;
        }

    } while (board[x][y] == ' '); 
    /*keep asking player to input another choice
    if the postion they pick is not empty*/
    
    return;
}

void computerMove()
{    
    printf("\n\nComputer's turn, please wait...\n");
    Sleep(1);
    do
    {
        srand(time(NULL));
        x= rand() % 3;
        y= rand() % 3;

        if (board[x][y] == ' ')
        {
            board[x][y] = comp; 
            //if the postion is free, put the computer's token there
            break;
        }
        else
        {
            continue;
        }
    } while (board[x][y] != ' '); 
    /*if that postion is occupued, keep generating a random position on
    the board until a free space is found*/

    return;
}

char checkWinner()
{
    //check rows
    for(int i=0; i<3; i++)
    {
        if((board[i][0] == board[i][1]) && (board[i][1] == board[i][2]))
        {
            return board[i][0]; 
        }
    }

    //check columns
    for(int j=0; j<3; j++)
    {
        if((board[0][j] == board[1][j]) && (board[1][j] == board[2][j]))
        {
            return board[0][j];
        }
    }
    
    //check diagonals
    if((board[0][0] == board[1][1]) && (board[1][1] == board[2][2]))
    {
        return board[0][0];
    }
    if((board[0][2] == board[1][1]) && (board[1][1] == board[2][0]))
    {
        return board[0][2];
    }

    return ' ';
}

void printWinner(char winner)
{
    if (winner == player)
    {
        printf("\t==> YOU WIN!\n\n");
    }
    else if (winner == comp)
    {
        printf("==> YOU LOSE!\n\n");
    }
    else
    {
        printf("==> Draw!\n\n");
    }
    return;
}