Qt: judge whether the string is in numeric format

Qt Development , You need to implement a basic function , Determine whether a string can be converted to a number , for example ：

123.45 Can be converted into numbers ;

123.BC Can't be converted to numbers ;

Qt How to judge in ？ Do some research , Found the answer :

bool isNum;
QString a = "123.56";
a.toDouble(&isNum);
qDebug() << "a isNum: " << isNum;

QString b = "123.BC";
b.toDouble(&isNum);
qDebug() << "b isNum: " << isNum;

Output ：

Reference resources ：

https://doc.qt.io/qt-5/qstring.html#toDouble