// OpenMP4.cpp : 定义控制台应用程序的入口点。
// 临界区方法进行求和
#include "stdafx.h"
#include <time.h>
#include <omp.h>
#include <Windows.h>
#define NUM_THREADS 2
int _tmain(int argc, _TCHAR* argv[])
{
clock_t t1, t2;
omp_set_num_threads(NUM_THREADS);
t1 = clock();
long long sum = 0;
#pragma omp parallel
{
long id = omp_get_thread_num();
long i;
long long sumtmp = 0;
for(i = id + 1; i <= 1000000000; i = i + NUM_THREADS) {
sumtmp= sumtmp + i;
}
#pragma omp critical
sum = sum + sumtmp;
}
t2 = clock();
printf("sum = %lld\n", sum);
printf("parallel time : %d\n", (t2 - t1));
t1 = clock();
sum = 0;
for(long i = 1; i <= 1000000000; i +&#