1.Qt Helper

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()).

2.示例

最后一个字符位置即字符串长度-1

    QString str = "hello world";
    qDebug() << "string at end: " << str.at(str.size() - 1);