C++ Exercises（二）

1，
#include<QApplication>
#include<Qlabel>

intmain(intargc,char*argv[])
{
QApplicationapp(argc,argv);
//QLabellbInfo("Hello,World",0);
QLabel*lbInfo=newQLabel("Hello,World",0);
//lbInfo.show();
lbInfo->show();
returnapp.exec();
}
2，
#include<QApplication>
#include<QPushButton>

intmain(intargc,char*argv[])
{
QApplicationapp(argc,argv);

//QPushButtonbtnOk("OK",0);
QPushButton*btnOk=newQPushButton("OK",0);
btnOk->resize(300,200);
QObject::connect(btnOk,SIGNAL(clicked()),&app,SLOT(quit()));//信号与槽联系起来
btnOk->show();
returnapp.exec();
}
3，
#include<QApplication>
#include<QWidget>
#include<QSlider>
#include<QSpinbox.h>

intmain(intargc,char*argv[])
{
QApplicationapp(argc,argv);

QWidget*centralwidget=newQWidget(0);

QSpinBox*spBox=newQSpinBox(centralwidget);
QSlider*slider=newQSlider(Qt::Horizontal,centralwidget);
spBox->setGeometry(QRect(20,20,44,22));
slider->setGeometry(QRect(90,20,160,21));
spBox->setRange(0,140);
slider->setRange(0,140);

QObject::connect(spBox,SIGNAL(valueChanged(int)),slider,SLOT(setValue(int)));//信号与槽联系起来
QObject::connect(slider,SIGNAL(valueChanged(int)),spBox,SLOT(setValue(int)));//信号与槽联系起来

spBox->setValue(32);
centralwidget->show();
returnapp.exec();
}