Prefix and Suffix of increasing and decreasing operators

[xbili]

I've just wrote a TicTacToe game for practice and here's what I have:

#include <iostream>

int checkwin();
void grid();

char square[10] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};

int main()
{

    int player=1, i, choice;
    char mark;
    
    do {
    grid();
    player = (player%2) ? 1:2;
    
    std::cout << "Player " << player << " enter a number:" << std::endl;
    std::cin >> choice;
    mark = (player==1) ? 'X':'O';
    
    if (choice == 1)
        square[1] = mark;
    else if (choice == 2)
        square[2] = mark;
    else if (choice == 3)
        square[3] = mark;
    else if (choice == 4)
        square[4] = mark;
    else if (choice == 5)
        square[5] = mark;
    else if (choice == 6)
        square[6] = mark;
    else if (choice == 7)
        square[7] = mark;
    else if (choice == 8)
        square[8] = mark;
    else if (choice == 9)
        square[9] = mark;
    else
    {
        std::cout << "That is not a correct input. Please try again.";
        player--;
        std::cin.ignore();
        std::cin.get();
    }
        
    i=checkwin();
        player++;
    } while (i==-1);
        
        if (i==1)
            std::cout << "Player " << --player << " has won the game!";
    if (i==0)
        std::cout << "It's a draw!";
    std::cin.ignore();
    std::cin.get();
    return 0;
    
}

int checkwin()
{
    if (square[1] == square[2] && square[2] == square[3])
        return 1;
    else if (square[4] == square[5] && square[5] == square[6])
        return 1;
    else if (square[7] == square[8] && square[8] == square[9])
        return 1;
    else if (square[1] == square[4] && square[4] == square[7])
        return 1;
    else if (square[2] == square[5] && square[5] == square[8])
        return 1;
    else if (square[3] == square[6] && square[6] == square[9])
        return 1;
    else if (square[1] == square[5] && square[5] == square[9])
        return 1;
    else if (square[3] == square[5] && square[5] == square[7])
        return 1;
    else if (square[1] != '1' && square[2] != '2' && square[3] != '3' && square[4] != '4' && square[5] != '5' && square[6] != '6' && square[7] != '7' && square[8] != '8' && square[9] != '9')
        return 0;
    else
    {
        return -1;
    }
}

void grid()
{
    std::cout << "   |   |   " << std::endl;
    std::cout << " " << square[1] << " | " << square[2] << " | " << square[3] << " " << std::endl;
    std::cout << "___|___|___" << std::endl;
    std::cout << "   |   |   " << std::endl;
    std::cout << " " << square[4] << " | " << square[5] << " | " << square[6] << " " << std::endl;
    std::cout << "___|___|___" << std::endl;
    std::cout << "   |   |   " << std::endl;
    std::cout << " " << square[7] << " | " << square[8] << " | " << square[9] << " " << std::endl;
    std::cout << "   |   |   " << std::endl;

    
}

However, I'm confused with the usage of the increasing and decreasing operator here. Especially when it comes to the printing of the winner. (Line 53)
--player
vs.
player--

I do know from the documentation that having the operator as a prefix means that the value of player would be decreased before an assignment to another variable, and if it's used as a suffix it means that it's being copied to another variable before decreasing.

But in this case I'm not assigning player as a value in any variables, so how would this affect my final results? Because if I used player--, my code would show that player 2 won, when in actual fact player 1 won.

Thanks for any help offered, I really appreciate it!

[Ispil]

Well, it strictly has to deal with order of events. In this case, player-- will take the current value of player, display it with cout, and then decrement it. --player will decrement it, then display it with cout.

[giblit]

I think you should error check before line 22. Then replace like 22-38 with square[ choice ] = mark; instead of all those if/else.

[Rechard3]

here's an easy-to-understand explanation:

consider the expression x--;, the value of x is decremented by 1, and the expression evaluates to the value of x before the decrement happened.
--x;, decrements x by 1, and the expression evaluates to the new value of x (after decrement).
increment is the same.
it might look confusing, but trust me, after you've used these expressions four-five times you'll get used to it, it's really simple.

[xbili]

Ispil & Rechard3:
I see, thanks for the insight! Really helped!

giblit:
Wow I didn't really think of it. Thanks for the tip!

[TheIdeasMan]

Also, checking for a win only needs to happen after there have been 6 turns in total, or 3 turns by one player.

HTH