// OpenMP1.cpp : 定义控制台应用程序的入口点。

//

#include "stdafx.h"

#include"omp.h"

#include<Windows.h>

#include<time.h>

#include<iostream>

using namespace std;

#define NUM_THREADS 4

int _tmain(int argc, _TCHAR* argv[])

	{

	 omp_set_num_threads(NUM_THREADS);

	 long long sum=0;

	 clock_t time_begin =clock();

	#pragma omp parallel for reduction(+:sum)

         for(long i=1;i<=1000000000;i++)

			  {

			   sum+=i;

			  }

	  clock_t time_end=clock();

	  double s1=time_end-time_begin;

	  cout<<"Sum="<<sum<<endl;

	  cout<<"并行时间="<<s1<<endl;

	//******************************************************

	  sum=0;

	  time_begin=clock();

	  for(long i=1;i<=1000000000;i++)

	  {

	   sum+=i;

	  }

	  time_end=clock();

	  double s2=time_end-time_begin;

	  cout<<"Sum="<<sum<<endl;

	  cout<<"串行时间="<<s2<<endl;

	  cout<<"加速比为"<<(s2/s1)<<endl;

	 system("pause");

	 return 0;

	}