QFrame *frame = new QFrame; frame->setLineWidth(2);
QVBoxLayout *layout = new QVBoxLayout; QFrame *frame1 = new QFrame; frame1->setLineWidth(3); layout->addWidget(frame1); QFrame *frame2 = new QFrame; frame2->setLineWidth(1); layout->addWidget(frame2);This code creates a vertical layout and adds two QFrame widgets. The first frame has a line width of 3 pixels, while the second frame has a line width of 1 pixel. Both frames are added to the layout and displayed. In summary, Cpp QFrame setLineWidth is a function used to set the width of the frame line for QFrame widgets in Qt C++. It is part of the Qt Widgets module, a package library in the Qt C++ framework used for creating graphical user interfaces.