程序小思考(一)

下面是一段小的程序，放在这里也算是对自己的一个提醒吧。

#include "graphicsview.h"#include <QApplication>int main(int argc, char *argv[]){    QApplication app(argc, argv);    GraphicsView view;    view.show();    return app.exec();}#ifndef GRAPHICSVIEW_H#define GRAPHICSVIEW_H#include <QGraphicsView>class GraphicsView : public QGraphicsView{public:    GraphicsView();};#endif // GRAPHICSVIEW_H#include "graphicsview.h"#include <QGraphicsScene>GraphicsView::GraphicsView(){    QGraphicsScene *scene = new QGraphicsScene;    scene->addLine(100,100,200,200);    setScene(scene);}