hints.md

AliRoot and AliPhysics documentations

The Doxygen documentation of AliROOT and AliPhysics is available here http://alidoc.cern.ch/ . It is generated daily.

Cleaning up and improving your code

• One of the most important things you can do is make sure your code is readable

• This means using whitespace freely, consistent indentation, etc

• This is valid C++ code:

    for(int i=0;i<10;i++){cout<<"i is "<<i<<endl;}

but it looks bad

• This is C++ code equivalent to that:

    for(int i=0; i<10; i++)
      {
        cout << "i is " << i << endl;
      }

and it looks much **better**

• There are no wrongs or rights, but be consistent

Fault tolerance

• Check e.g. the snippet

    for(Int_t i(0); i < iTracks; i++) {
        // loop over all the tracks
        AliAODTrack* track = static_cast<AliAODTrack*>(fAOD->GetTrack(i));
        // fill our histogram
        fHistPt->Fill(track->Pt());
    }

• We can build in fault tolerance:

    for(Int_t i(0); i < iTracks; i++) {
        // loop over all the tracks
        AliAODTrack* track = static_cast<AliAODTrack*>(fAOD->GetTrack(i));
        if(!track) continue;
        // fill our histogram
        fHistPt->Fill(track->Pt());
    }

• Finally, it’s a very good idea to comment your code

• Comments improve readability and maintainability

• Comments should be useful, though, and comments that are overly obvious can be avoided

    // no comment: bad
    a++;
    
    // pointless comment, also not so good

    a++; // adding 1 to a

    
    // descriptive comment, very good

    a++; // adding 1 to a to make a point during a tutorial

• It’s also a good idea to document your code as you’re writing it - you will forget how it works and no-one will continue with uncommented tasks