Qt - QTreeWidget Tree Traversal

Need to use QTreeWidgetItemIterator class：

//Each item in a tree, checking the text in the first column 
//against a user-specified search string.
QTreeWidgetItemIterator it(treeWidget);
while (*it) {
    if ((*it)->text(0) == itemText)
        (*it)->setSelected(true);
    ++it;
}

Note: The above code is excerpted from Qt documentation.