1 player tic tac toe for ICS4U

tictactoe.c

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <time.h>

char board[9];

bool win()
{
    // row checking
    for (int i = 0; i < 3; i++)
        if (board[i] == ' ')
            continue;
        else if (board[i] == board[i + 3] && board[i] == board[i + 6])
            return true;

    // column checking
    for (int i = 0; i < 7; i += 3)
        if (board[i] == ' ')
            continue;
        else if (board[i] == board[i + 1] && board[i] == board[i + 2])
            return true;

    // diagonal checking
    
        if (board[4] != ' ' && ((board[0] == board[4] && board[0] == board[8]) || (board[2] == board[4] && board[2] == board[8])))
            return true;

    return false;
}

bool taken(int pos)
{
    if (board[pos] == ' ')
        return false;
    return true;
}

void print()
{
    // id rather not improve this
    printf("\n %c | %c | %c \
        \n---+---+---\
        \n %c | %c | %c \
        \n---+---+---\
        \n %c | %c | %c \n\n",
           board[0],
           board[1],
           board[2],
           board[3],
           board[4],
           board[5],
           board[6],
           board[7],
           board[8]);
}

int main()
{
    srand(time(NULL));

    printf("Welcome to single player Tic-Tac-Toe!\n\
        \nBoard Positions:\
        \n 1 | 2 | 3 \
        \n---+---+---\
        \n 4 | 5 | 6 \
        \n---+---+---\
        \n 7 | 8 | 9 \n\n");

    // clear array to space chars
    for (int i = 0; i < 9; i++)
        board[i] = ' ';

    // game
    while (true)
    {

        print();

        int in = 0;

        printf("Please enter a number: ");
        scanf("%d", &in);

        while (in == 0 || taken(in - 1) || in > 9)
        {
            printf("Number invalid, please pick a different number: ");
            scanf("%d", &in);
        }

        board[in - 1] = 'X';

        if (win())
        {
            print();
            printf("You won!\n");
            return 0;
        }

        int computer = 0;

        while (computer == 0 || taken(computer - 1))
            computer = (rand() % 9) + 1;

        board[computer - 1] = 'O';

        if (win())
        {
            print();
            printf("You lost!\n");
            return 0;
        }
    }

    return 0;
}