Hi
after some months learing basics of C++, today i started by creating a simple game
but i have a problem

checkwin() doesn't work properly

sorry for my english

#include <iostream>

using namespace std;

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

void GameBoard();
int checkwin();

int main(){

    GameBoard();
    int choice, i;
    int player = 1;
    char mark;
    do{
        if (player == 1)
            mark = 'X';
        else
            mark = 'O';
        cout << "Player " << player << " Enter a number: ";
        cin >> choice;
        if (choice == 1 && square[1] == '1')
            square[1] = mark;
        else if (choice == 2 && square[2] == '2')
            square[2] = mark;
        else if (choice == 3 && square[3] == '3')
            square[3] = mark;
        else if (choice == 4 && square[4] == '4')
            square[4] = mark;
        else if (choice == 5 && square[5] == '5')
            square[5] = mark;
        else if (choice == 6 && square[6] == '6')
            square[6] = mark;
        else if (choice == 7 && square[7] == '7')
            square[7] = mark;
        else if (choice == 8 && square[8] == '8')
            square[8] = mark;
        else if (choice == 9 && square[9] == '9')
            square[9] = mark;
        else
        {
            cout << "This Block already taken!" << endl;
            player--;
        }
        if (player == 1)
            player++;
        else
            player--;
        system("cls");
        GameBoard();
        i = checkwin();
    } while (i=-1);

    if (i == 1){
        cout << "Player " << player << "is win!" << endl;
    }
    else{
        cout << "Draw!" << endl;
    }
    cin.ignore();
    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 GameBoard(){
    cout << "         Tic Tac Toe         " << endl << endl;
    cout << "Player 1: X , Player 2: O" << endl;
    cout << "   | " << "  |   " << endl;
    cout << " " << square[1] << " | " << square[2] << " | " << square[3] << " " << endl;
    cout << "___ ___ ___" << endl;
    cout << "   | " << "  |   " << endl;
    cout << " " << square[4] << " | " << square[5] << " | " << square[6] << " " << endl;
    cout << "___ ___ ___" << endl;
    cout << "   | " << "  |   " << endl;
    cout << " " << square[7] << " | " << square[8] << " | " << square[9] << " " << endl;

}

Hello, while I am not sure I fully understand the way you have done this, I have spotted something that looks suspect.

GameBoard();
i = checkwin();
} while (i=-1);

the condition in the do while loop, you are assigning i to -1, not checking for equality, are you sure this is not what you want
}while (i==-1);

EDIT:

I just compiled this, I was correct, change your while condition to what I have and it will work, though now you have another bug, the incorrect player is credited with the win, happy debugging and don't worry, everyone on this site has made the double equals error, probably more than once, you are doing great!

Hello, while I am not sure I fully understand the way you have done this, I have spotted something that looks suspect.

GameBoard();
i = checkwin();
} while (i=-1);

the condition in the do while loop, you are assigning i to -1, not checking for equality, are you sure this is not what you want
}while (i==-1);

EDIT:

I just compiled this, I was correct, change your while condition to what I have and it will work, though now you have another bug, the incorrect player is credited with the win, happy debugging and don't worry, everyone on this site has made the double equals error, probably more than once, you are doing great!

OMG i can't believe i made this mistake i was trying to solve this problem the whole night >_< but i couldn't figure out what the problem is

Thank you

One other thing you can do, though disliked by many coders is yoda conditions.

This is where instead of i==-1 you write -1==i

If you forget an equals, the compiler will show an error because you cannot assign a value to a constant