#include<stdio.h>
#include<stdlib.h>
#define n 16

static int board[n][n];
int i, j, x, y;
int choice;



void main_menu(void)
{
    printf("\n==========5 chess game==========\n");
    printf("    1.Start a new game\n");
    printf("    2.Continue\n");
    printf("    3.Exit");
    printf("\n================================\n");
    printf("Enter : \n");

}

void initialize_board()  /* reset a blank board */
{
    for(i=0; i<16; i++)
        for(j=0; j<16; j++)
            board[i][j]=0;
}

void read_board(void)
{
    FILE *file = fopen("board.txt" , "r");
    for(i=0; i<17; i++)
        for(j=0; j<17; j++)
            fscanf(file, "%d", &board[i][j]);
    fclose(file);
}

void write_board(void)
{
    FILE *file = fopen("board.txt" , "w");
    for(i=0; i<16; i++)
        for(j=0; j<16; j++)
            fprintf(file, "%d", board[i][j]);
    fclose(file);
}

void output_board(void)  /* print the chess board */
{
    int a=0, b=0;

    for(i=0; i<16; i++)  /* print the 5 chess x-coordinates */
        printf("%3d", a++);
    printf("\n");

    for(i=0; i<16; i++)
    {
        printf("%2d", b++);  /* print the 5 chess y-coordinates */
        for(j=0; j<16; j++)
        {
            if(board[i][j]==0)
                printf("+  ");
            else if(board[i][j]==1)
                printf("o  ");
            else if(board[i][j]==2)
                printf("x  ");
        }
        printf("\n");
    }
}

void range_check(int p)  /* check if the position is in the board range */
{
    if(x>=0 && x<16 && y>=0 && y<16);  //in the borad range, continue

    else if(x<0 || x>=16 || y<0 || y>=16)  //not in the board range, run the following statements
    {
        printf("\nError.\n");
        printf("\n player%d--enter the position (y/x) : ", p);
        scanf("%d %d", &x, &y);
        range_check(p);
    }
}

void occupasion_check(int p)  /* check if the position has already occupied */
{
    if(board[x][y]==0);  //not occupied, continue

    else if(board[x][y]==1 || board[x][y]==2)  //occupied, run the following statements
    {
        printf("\nError.\n");
        printf("\n player%d--enter the position (y/x) : ", p);
        scanf("%d %d", &x, &y);
        occupasion_check(p);
    }
}





int main(void)
{
    int p, k;

    main_menu();
    scanf("%d", &choice);
    switch(choice)
    {
        case 1: read_board();
                do
                {
                    /* player1 playing */
                    system("cls");
                    p=1;
                    output_board();
                    printf("\n player%d--enter the position (y/x) : ", p);
                    scanf("%d %d", &x, &y);
                    range_check(p);
                    occupasion_check(p);
                    board[x][y]=1;
                    write_board();

                    /* player2 playing */
                    system("cls");
                    p=2;
                    output_board();
                    printf("\n player2--enter the position (y/x) : ", p);
                    scanf("%d %d", &x, &y);
                    range_check(p);
                    occupasion_check(p);
                    board[x][y]=2;
                    write_board();

                    k=1;
                    //k=2;
                }while(k==1);

                break;

        case 2: read_board();
                output_board();
                break;

        case 0: break;
    }
}