怎么读取QString 第i个位置的字符？
------解决思路----------------------
sorry，刚才看错了，以为是第1个字符。
获取第i个字符的方法如下：
const QChar QString::at(int position) const
Returns the character at the given index position in the string.
The position must be a valid index position in the string (i.e., 0 <= position < size()).
See also operator[]().