#include <QtGui/QApplication>#include <QTreeWidget>#include <QDebug>// 定义结构体，只包括四个指针typedef struct {      char * sect_id, * title, * page_num;      char * parent_id;  } SectionInfo;  // 注意1，靠内容（最后一项）来设置上下级关系// 注意2，它们不是按顺序排列的SectionInfo directory[] = {      {"Chapter 1",     "The Prehistory of C++",          "19",   ""},      {"Chapter 2",     "C with Classes",                 "27",   ""},      {"Section 1.1",   "Simula and Distributed Systems", "19",   "Chapter 1"},      {"Section 1.2",   "C and Systems Programming",      "22",   "Chapter 1"},      {"Section 2.4",   "Run-Time Efficiency",                "32",   "Chapter 2"},      {"Section 2.4.1", "Inlining",                       "33",   "Section 2.4"},  };  int main(int argc, char *argv[])  {      QApplication app(argc, argv);      QTreeWidget * treeWidget = new QTreeWidget();      // 设置列数（赤裸裸简单规定多少列的情况不多见啊）    treeWidget->setColumnCount(3);     // 设置表头    QStringList headers;      headers << "Section Number" << "Title" << "Page Number";      treeWidget->setHeaderLabels(headers);                           // 循环一共执行六次    for (int i=0; i<sizeof(directory)/sizeof(directory[0]);  i++) {          SectionInfo info = directory[i]; // 给C++结构体赋值，还挺巧妙的         QTreeWidgetItem * item=NULL;          if (strcmp(info.parent_id, "")==0 ){              item = new QTreeWidgetItem(treeWidget); // 设置一行依附于整体        }else{              QString parent_id(info.parent_id); // 取得当前行父节点的文字，用于比较            QTreeWidgetItemIterator  it (treeWidget); // 取得整体treeWidget的迭代子项，注意是一行一行迭代            // 直到i=4，才会进入while循环，0和1不会进入else，2和3第一次比较就不成立，所以不会进入while            while ( (*it)->text(0) != parent_id) { // text(0)是QTreeWidgetItem的函数，即第零列的文字                qDebug() << i << "  " << (*it)->text(0);                ++it;              }            item = new QTreeWidgetItem( *it ); // 把最后一行空迭代子项变成一行，并把找到的节点设为父节点 good         }          // 有了item及可以设置内容了        if ( item) {              item->setText(0, info.sect_id);              item->setText(1, info.title  );              item->setText(2, info.page_num);          }      }         treeWidget->resize(400,200);      treeWidget->show();      return app.exec();  }