使用QT在windows下高精度测试程序运行时间

#include <QTime>
#include <QApplication>
#include <QMessageBox>
#include <QWidget>
#include <QLabel>
#include <windows.h>
using namespace std;
void caculate()
{
for(int i=0;i<32323;i++)
{
for(int j=0;j<32323;j++) ;
}
}
int main(int argc, char *argv[])
{
QApplication a(argc, argv);

QWidget *w = new QWidget;
QLabel *label1,*label2,*label3,*label4;
//QTime mytime = QTime::currentTime ();
//QMessageBox::warning(w,"test time", mytime.toString());//debug
LARGE_INTEGER litmp;
LONGLONG Qpart1,Qpart2,Useingtime;
double dfMinus,dfFreq,dfTime;

//获得CPU计时器的时钟频率
QueryPerformanceFrequency(&litmp);//取得高精度运行计数器的频率f,单位是每秒多少次（n/s），
dfFreq = (double)litmp.QuadPart;

QueryPerformanceCounter(&litmp);//取得高精度运行计数器的数值
Qpart1 = litmp.QuadPart; //开始计时

caculate(); //待测试的计算函数等
QueryPerformanceCounter(&litmp);//取得高精度运行计数器的数值
Qpart2 = litmp.QuadPart; //终止计时

label1 = new QLabel("Start Countor:"+QString::number(Qpart1,10),w);
label1->setGeometry(10,10,200,30);
label2 = new QLabel("Use Countor:"+QString::number((Qpart2-Qpart1),10),w);
label2->setGeometry(10,50,200,30);
label3 = new QLabel("End Countor:"+QString::number(Qpart2,10),w);
label3->setGeometry(10,90,200,30);

dfMinus = (double)(Qpart2 - Qpart1);//计算计数器值
dfTime = dfMinus / dfFreq;//获得对应时间，云锡摇床。单位为秒,可以乘精确到微秒级（us）
Useingtime = dfTime*1000000;
label4 = new QLabel("Use Time:"+QString::number(Useingtime,10)+" us",w);
label4->setGeometry(10,120,200,30);
w->setMinimumSize(300,200);
w->setMaximumSize(300,200);
w->show();

return a.exec();
}