c++面试题
#include <QtGui/QApplication>
#include "mainwindow.h"
#include <QMessagebox>
class CB{
public:
virtual void OutString(const char* str="CB:Outstring")
{
QMessageBox::information(NULL, "EnQStrXml", "Call CB::Outstring(...)");
QMessageBox::information(NULL, "EnQStrXml", str);
}
};
class CD:public CB{
public:
virtual void OutString(const char* str="CD:Outstring")
{
QMessageBox::information(NULL, "EnQStrXml", "Call CD::Outstring(...)");
QMessageBox::information(NULL, "EnQStrXml", str);
}
};
void TestOutString(CB& cb)
{
cb.OutString();
}
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
// MainWindow w;
//w.show();
CB cbobj;
CD cdobj;
cbobj.OutString(); //Call CB::Outstring(...) CB:Outstring
cdobj.OutString();//Call CD::Outstring(...) CD:Outstring
cbobj.OutString("Hello World");//Call CB::Outstring(...) Hello World
cdobj.OutString("welcome to cnit");//Call CB::Outstring(...) welcome to cnit
TestOutString(cbobj);// Call CB::Outstring(...) CB:Outstring
TestOutString(cdobj);// Call CD::Outstring(...) CB:Outstring
return a.exec();
}