    //=============================================================================
    //  MuseScore
    //  Music Composition & Notation
    //
    //  Copyright (C) 2002-2011 Werner Schweer
    //
    //  This program is free software; you can redistribute it and/or modify
    //  it under the terms of the GNU General Public License version 2
    //  as published by the Free Software Foundation and appearing in
    //  the file LICENCE.GPL
    //=============================================================================

    #ifndef __DRUMSET_H__
    #define __DRUMSET_H__

    #include "mscore.h"
    #include "note.h"

    namespace Ms {

    class XmlWriter;

    //---------------------------------------------------------
    //   DrumInstrument
    //---------------------------------------------------------

    struct DrumInstrument {
          QString name;
          NoteHead::Group notehead; ///< notehead symbol set
          int line;                 ///< place notehead onto this line
          Direction stemDirection;
          int voice;
          char shortcut;            ///< accelerator key (CDEFGAB)

          DrumInstrument() {}
          DrumInstrument(const char* s, NoteHead::Group nh, int l, Direction d,
             int v = 0, char sc = 0)
             : name(s), notehead(nh), line(l), stemDirection(d), voice(v), shortcut(sc) {}
          };

    static const int DRUM_INSTRUMENTS = 128;

    //---------------------------------------------------------
    //   Drumset
    //    defines noteheads and line position for all
    //    possible midi notes in a drumset
    //---------------------------------------------------------

    class Drumset {
          DrumInstrument _drum[DRUM_INSTRUMENTS];

       public:
          bool isValid(int pitch) const             { return _drum[pitch].notehead != NoteHead::Group::HEAD_INVALID; }
          NoteHead::Group noteHead(int pitch) const { return _drum[pitch].notehead;       }
          int line(int pitch) const                 { return _drum[pitch].line;           }
          int voice(int pitch) const                { return _drum[pitch].voice;          }
          Direction stemDirection(int pitch) const  { return _drum[pitch].stemDirection;  }
          const QString& name(int pitch) const      { return _drum[pitch].name;           }
          int shortcut(int pitch) const             { return _drum[pitch].shortcut;       }

          void save(XmlWriter&) const;
          void load(XmlReader&);
          bool readProperties(XmlReader&, int);
          void clear();
          int nextPitch(int) const;
          int prevPitch(int) const;
          DrumInstrument& drum(int i) { return _drum[i]; }
          const DrumInstrument& drum(int i) const { return _drum[i]; }
          };

    extern Drumset* smDrumset;
    extern Drumset* gpDrumset;
    extern void initDrumset();

    }     // namespace Ms
    #endif

↑ V730 Not all members of a class are initialized inside the constructor. Consider inspecting: notehead, line, voice, shortcut.