Using of QuadSplitter for Qt

QuadSplitter qs(0);
qs.resize(500, 500);

QWidget* _one = new QPushButton(&qs);
_one->setStyleSheet("background:red");
QWidget* _two = new QPushButton(&qs);
_two->setStyleSheet("background:green");

QWidget* _three = new QPushButton(&qs);
_three->setStyleSheet("background:blue");
QWidget* _four = new QPushButton(&qs);
_four->setStyleSheet("background:yellow");

qs.addWidget(_one, 0,0);
qs.addWidget(_two, 0,1);
qs.addWidget(_three, 1,0);
qs.addWidget(_four, 1,1);

qs.show();