#include <qapplication.h>#include <qpushbutton.h>#include <qfont.h>#include <qmultilineedit.h>#include <qscrollview.h>#include <qwidget.h>class MyMainWindow:public QScrollView{ public:    MyMainWindow(); private:    QWidget *main;    QPushButton *b1;    QPushButton *b2;    QPushButton *b3;    QPushButton *b4;    QPushButton *b5;    QMultiLineEdit *edit1;};MyMainWindow::MyMainWindow(){ setGeometry(100,100,470,410);  main = new QWidget(this); main->resize(460,400); b1 = new QPushButton("New",main); b1->setGeometry(10,10,80,30); b1->setFont(QFont("Times",18,QFont::Bold)); b2 = new QPushButton("Open",main); b2->setGeometry(100,10,80,30); b2->setFont(QFont("Times",18,QFont::Bold)); b3 = new QPushButton("Save",main); b3->setGeometry(190,10,80,30); b3->setFont(QFont("Times",18,QFont::Bold)); b4 = new QPushButton("Print",main); b4->setGeometry(280,10,80,30); b4->setFont(QFont("Times",18,QFont::Bold)); b5 = new QPushButton("Quit",main); b5->setGeometry(370,10,80,30); b5->setFont(QFont("Times",18,QFont::Bold)); edit1 = new QMultiLineEdit(main); edit1->setGeometry(0,50,440,340); edit1->setText("Let's pretend this is a text editor."); //we must call the QScrollView::addChild function for each of its child widgets. addChild(main);}main(int argc,char **argv){ QApplication a(argc,argv); MyMainWindow w; a.setMainWidget(&w); w.show(); a.exec();}