为什么QT需要封装QString，而不需要封装 int double ？？？？ 真心求解

Question

做了一些QT的小项目，自己也写了 QStingtoStr的一些转换函数，可是不懂QT为什么非要把string给封装了，又不提供转换的函数。

Answer 1

下面这些还不够吗，还要自己写转换方法？
std::string QString::toStdString () const
Returns a std::string object with the data contained in this QString. The Unicode data is converted into 8-bit characters using the toAscii() function.

This operator is mostly useful to pass a QString to a function that accepts a std::string object.

If the QString contains Unicode characters that the QTextCodec::codecForCStrings() codec cannot handle, using this operator can lead to loss of information.

This operator is only available if Qt is configured with STL compatibility enabled.

See also toAscii(), toLatin1(), toUtf8(), and toLocal8Bit().