Let's buckle up and do this project! Create a new Qt Widgets Application project named ch11-drum-machine. As usual, add the CONFIG += c++14 in ch11-drum-machine.pro.

Now, create a new C++ class named SoundEvent. Here is SoundEvent.h stripped of its functions:

#include <QtGlobal> 
 
class SoundEvent 
{ 
 
public: 
    SoundEvent(qint64 timestamp = 0, int soundId = 0); 
    ~SoundEvent(); 
 
    qint64 timestamp; 
    int soundId; 
}; 

This class contains only two public members:

• timestamp: A qint64 (of the long long type) that contains the current time of the SoundEvent in milliseconds since the beginning of the track
• soundId: The ID of the sound that has been played

In recording mode, each time the user plays a sound, a SoundEvent is created with the appropriate data. The content of the SoundEvent.cpp file is so boring that we will not inflict...