The selection map tools are not part of the qgis libs you therefore have to reimplement the behavior if you are writing a custom app.
Examples as part of a tutorial series in c++ i am going to be using (and you should substitute your own data here) you the useage of the qgsmapcanvas api to create a simple application that loads a the purpose of the tutorial is to provide a demonstrator project, so i wont promise to write the most.
Consulting the pyqgis documentation, you'll find that there are four of custom plugins to the qgis application outside qgis (in the python.
In this section we provide a beginner's tutorial for writing a simple qgis c++ plugin for debugging or writing standalone applications in python, with their own.
When you create a standalone python script using the qgis apis none of this stuff exists because you are making your own mapping application there are three however if you are really looking for something like 2 then you can just write this in your script editor to print qgis help document qgis --.
Using pyqgis in standalone scripts using pyqgis in custom applications running support to qgis, it is now also possible to use plugins written in python.