#includeIn this example, we create a horizontal layout and add two labels to it. We then set the layout's size constraint to QLayout::SetMaximumSize, which means the layout's size will be at most the maximum size of its contents. Finally, we set the layout on a window and display it. Overall, the QHBoxLayout setSizeConstraint method allows you to control the size of a horizontal layout in Qt.#include #include #include int main(int argc, char *argv[]) { QApplication app(argc, argv); QWidget window; QHBoxLayout *layout = new QHBoxLayout; QLabel *label1 = new QLabel("Hello"); QLabel *label2 = new QLabel("World"); layout->addWidget(label1); layout->addWidget(label2); layout->setSizeConstraint(QLayout::SetMaximumSize); window.setLayout(layout); window.show(); return app.exec(); }