// 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;
}