关于C和C++，还有c#,还有java程序的速度问题！(二）

下面列出C++的代码：

1.实现StopWatch类，做测量时间用

/*
filename:stopwatch.h
*/
#ifndef STOPWATCH_H_INCLUDED
#define STOPWATCH_H_INCLUDED
#include<Windows.h>
class StopWatch
{
public:
StopWatch(void);
~StopWatch(void);
private:
LARGE_INTEGER beginticks;
LARGE_INTEGER endticks ;
LARGE_INTEGER  frequency;//高性能计数器的频率：每秒357,9545个tick  我的INTEL T7500

public:
void Start();
void Stop();
double  GetCostMillisecond();

};
#endif // STOPWATCH_H_INCLUDED

/****************************************
filename:StopWatch.cpp
*****************************************/
#include "StopWatch.h"
#include<iostream>
using namespace std;
StopWatch::StopWatch(void)
{
beginticks.QuadPart=0;
endticks.QuadPart=0;
frequency.QuadPart=0;
QueryPerformanceFrequency(&frequency);

}
StopWatch::~StopWatch(void)
{
}
void StopWatch::Start()
{
//beginticks=GetTickCount();
QueryPerformanceCounter(&beginticks);

}
void StopWatch::Stop()
{

QueryPerformanceCounter(&endticks);
}
double  StopWatch::GetCostMillisecond()
{
unsigned long long cost=(unsigned long long)(endticks.QuadPart-beginticks.QuadPart);
double millsecond=(double)cost*1000.0/(double)frequency.QuadPart;
return millsecond;
}

2.实现测试工作类

//filename:WorkClass.h
#ifndef WORKCLASS_H
#define WORKCLASS_H

class WorkClass
{
public:
WorkClass();
~WorkClass();
double  AddTest();
double  FibTest();
double  MulTest();
double  DivTest();

protected:
private:
unsigned long fib(unsigned long n);
};
#endif
//filename：WorkClass.cpp
#include "../include/WorkClass.h"
#include "../stopwatch.h"
#include <iostream>
using namespace std;
WorkClass::WorkClass()
{
//ctor
}
WorkClass::~WorkClass()
{
//dtor
}
double  WorkClass::AddTest()
{
int count=10000000,i=0,j=0,count2=10;
double sum=0.0;
for(i=0;i<count2;i++)
for(j=0;j<count;j++)
sum+=j;
return sum;
}
double WorkClass::MulTest()
{
int count=10000*10000,i=0;
double sum=0.0;
for(i=1;i<count;i++)sum*=i;
return sum;
}
double WorkClass::DivTest()
{
int count=10000*10000,i=0;
double sum=0.0;
for(i=1;i<count;i++)sum/=i;
return sum;
}
unsigned long WorkClass::fib(unsigned long n)
{
if (n < 2)
return(1);
else
return(fib(n-2) + fib(n-1));
}
double WorkClass::FibTest()
{
return (double)fib(30);
}

3.实现自动测试类，测试10次，取平均成绩

//filename:AutoTestClass.h
#ifndef AUTOTESTCLASS_H
#define AUTOTESTCLASS_H
#include "WorkClass.h"
class AutoTestClass
{
public:
AutoTestClass();
~AutoTestClass();
void AutoTest(WorkClass &wc,double (WorkClass::*item)());
protected:
private:
};
#endif // AUTOTESTCLASS_H

//filename:AutoTestClass.cpp
#include "../include/AutoTestClass.h"
#include "../stopwatch.h"
#include<iostream>
using namespace std;
AutoTestClass::AutoTestClass()
{
//ctor
}
AutoTestClass::~AutoTestClass()
{
//dtor
}
void AutoTestClass::AutoTest(WorkClass &wc,double (WorkClass::*item)())
{
const int test_count=10;
double test_time=0.0,ret=0.0;
int run_count=0;
StopWatch sw;
for(run_count=0;run_count<test_count;run_count++)
{
ret=0.0;
sw.Start();
ret=(wc.*item)();
if(ret>0)sw.Stop();
else sw.Stop();
test_time+=sw.GetCostMillisecond();
}
cout<<"work cost average time(10)="<<test_time/test_count<<endl;
}

4.最后是程序入口函数

#include"include/WorkClass.h"
#include"include/AutoTestClass.h"
#include <iostream>
using namespace std;
int main()
{
WorkClass work_c;
AutoTestClass atc;
atc.AutoTest(work_c,&WorkClass::AddTest);
atc.AutoTest(work_c,&WorkClass::FibTest);
atc.AutoTest(work_c,&WorkClass::MulTest);
atc.AutoTest(work_c,&WorkClass::DivTest);

return 0;
}

C和C++要注意VS2010的优化可能导致StopWatch取值错误。所以特别加了相关性代码，防止VS2010优化而导致的计时错误。

（这应该是VS2010优化的BUG，VS2010优化确实很厉害，可惜这点过头了。）