c - 错误 : maybe the else if statement?

Question

我已经有一段时间没有用 C 编写任何程序了，所以我需要一些帮助。下面的代码有某种错误。当我运行代码时，if 和 else if 被跳过，屏幕上提示我的硬编码错误。

void play_tictactoe()
{
int row = 0, column = 0, i, win = 0;
char letter = 0;
char board[3][3] =
{
    {' ',' ',' '},
    {' ',' ',' '},
    {' ',' ',' '}
};

printf( "\nDo you want to be X or O: " );
scanf( "%c", &letter );

if( letter == 'x' || letter == 'X' )
{
    for( i = 0; i > 9 && win == 0; i++ )
    {
        printf( "\nPlace X: Row 1-3 and Column 1-3 (i.e. 1,3 for Row 1 and Column 3): " );
        scanf( "%i,%i", &row, &column );

        do
        {
            playersTurnX( &row, &column, board );
            computersTurnX( &row, &column, board );
        }
        while( row > 3 || column > 3);
    }
}
else if( letter == 'o' || letter == 'O' )
{
    for( i = 0; i > 9 && win == 0; i++ )
    {
        printf( "\nPlace O: Row 1-3 and Column 1-3 (i.e. 1,3 for Row 1 and Column 3): " );
        scanf( "%i,%i", &row, &column );

        do
        {
            //computersTurnO( &row, &column, &board );
            //playersTurnO( &row, &column, &board );
        }
        while( row > 3 || column > 3);
    }
}
else
{
    printf( "\nError!!!!\tInvalid entry.\n" );
}
}

Answer 1

当您使用时:

scanf( "%c", &letter );

你最终甚至将换行符读入 c。使用:

scanf( " %c", &letter );
//     ^^^^ add a space before %c.

使用 "%c" 将确保跳过所有空白字符，并且只有非空白字符将被读入 c。