Issue Switching Players - Tic Tac Toe

Question

I have an issue where I can't seem to switch players (from X to O) correctly, it just switches randomly between the two. Here is my code so far:

#include <iostream>
#include <conio.h>
#include <windows.h>
using namespace std;

bool gameover = false;
char position[3][3] = {'1', '2', '3', '4', '5', '6', '7', '8', '9'};
char player = 'X';
char player2 = 'O';
void draw(){
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            cout << position[i][j] << " ";
        }
        cout << endl;
    }
}


void input(){
    if (_kbhit()) {
        switch (_getch())
        {
        case '1':
            position[0][0] = player;
            break;
        case '2':
            position[0][1] = player;
            break;
        case '3':
            position[0][2] = player;
            break;
        case '4':
            position[0][3] = player;
            break;
        case '5':
            position[0][4] = player;
            break;
        case '6':
            position[0][5] = player;
            break;
        case '7':
            position[0][6] = player;
            break;
        case '8':
            position[0][7] = player;
            break;
        case '9':
            position[0][8] = player;
            break;
        }
    }

}

void logic() {
    if (player == 'X') {
        player = 'O';
    }
    else {
        player = 'X';
    }
}

int main (){
    while (!gameover) {
        input();
        draw();
        logic();
        system("cls");
    }
    return 0;
}

I'm sorry if this question has been asked so many times before, but I just can't seem to find a fix. I've tried changing system ('cls') to pause instead but doesn't work either.

first problems lies with how you're assessing the `position` multidimensional array. — Kagiso Marvin Molekwa, Jan 22 '20 at 19:10
Try to print the what `_getch` returns, you probably get unhandle char (not in 0-9) here that doesn't modify the game (ignored in the switch) but the player switch anyway (input should not return until a valid move is played). — Orace, Jan 22 '20 at 19:15
@marvinIsSacul It's weird, but technically valid (OP is not accessing array outside of bounds). — Yksisarvinen, Jan 22 '20 at 19:16

nephewtom · Accepted Answer · 2020-01-27T13:24:25.303

0

Checking _kbhit() function documentation:

_kbhit returns a nonzero value if a key has been pressed. Otherwise, it returns 0.

So, if the user is not pressing any key, _kbhit() returns 0.
input() function exits and while loop is constantly changing player variable when the user does nothing...

When you fix that, your code should handle the positions already played.
By the way, do you want to draw that all the time?
It seems you do not need to do it until a valid movement happens.

edited Jan 27 '20 at 13:24

answered Jan 22 '20 at 20:38

nephewtom

2,941
3
35
49

Thanks for looking this up. With this mind, I resorted to making if and else statements instead and works (finally!!). Sorry what do mean by 'draw that all the time'? (Not familiar with the lingo haha). Thanks a lot for your help. – Mars_1996 Jan 26 '20 at 13:25
Actually, I just tested it and instead of using if statements, I can still use switch statements, which is what I wanted to do initially. – Mars_1996 Jan 26 '20 at 13:47
In your original `main()` program you are using a conventional game-loop which normally does: `1-getUserInput, 2-updateGameState, 3-drawGame` (the order could vary). But since you are "drawing" it on the CMD terminal and will only need to be drawn if there is a valid input, you probably can just draw it in that case, and avoid the unnecessary flickering. – nephewtom Jan 27 '20 at 14:11

Issue Switching Players - Tic Tac Toe

1 Answers1