QTreeWidgetItem* root = new QTreeWidgetItem(); root->setText(0, "Root"); QTreeWidgetItem* child1 = new QTreeWidgetItem(root); child1->setText(0, "Child 1"); QTreeWidgetItem* child2 = new QTreeWidgetItem(root); child2->setText(0, "Child 2"); QTreeWidgetItem* subchild = new QTreeWidgetItem(child2); subchild->setText(0, "Sub Child");In this example, a new QTreeWidgetItem is created and assigned as the root item. Two child items are created and assigned to the root item, each with their own text. A third child item is created and assigned to the second child, forming a three-level tree. Package library: Qt library.