多线程测试

#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>
#include <stdio.h>

int g_num = 1;
pthread_mutex_t mutex;
pthread_cond_t cond1,cond2;

void* thread1(void* arg)
{
    int flag1=0;
	while(1)
	{
        flag1++;
		pthread_mutex_lock(&mutex);
        srand((unsigned int)time(NULL));

        if((g_num=rand()*2+1)>0)
        {
            printf("%d奇数随机数为：%d\n",flag1,g_num);
        }
        else{
            printf("%d奇数随机数为：%d\n",flag1,-g_num);
        }
        pthread_cond_signal(&cond2);
        pthread_cond_wait(&cond1,&mutex);		
		pthread_mutex_unlock(&mutex);
		sleep(1);
        if (flag1==10)
        {
            break;
        }
        
        
	}
	return NULL;
}

void* thread2(void* arg)
{
      int flag2=0;
	while(1)
	{
         flag2++;
        //这个sleep(1)加在前面是因为开启线程时有可能是线程2先打印，
        //导致变成thread2输出奇数，threa1输出偶数。为了避免这种情况，可以在延迟下线程2的打印。
        sleep(1);
        srand((unsigned int)time(NULL));

        if((g_num=rand()*2)>0)
        {
            printf("%d偶数随机数为：%d\n", flag2,g_num);
        }
        else{
            printf("%d偶数随机数为：%d\n",flag2,-g_num);
        }
		
		pthread_mutex_lock(&mutex);

        pthread_cond_signal(&cond1);
        pthread_cond_wait(&cond2,&mutex);
		pthread_mutex_unlock(&mutex);
        if (flag2==10)
        {
            break;
        }
		
	}
	return NULL;
}
int main()
{
	pthread_t p1,p2;
	
	pthread_mutex_init(&mutex,NULL);
	pthread_cond_init(&cond1,NULL);
	pthread_cond_init(&cond2,NULL);	
	
	pthread_create(&p1,NULL,thread1,NULL);
	pthread_create(&p2,NULL,thread2,NULL);
    pthread_join(p1,NULL);
	pthread_join(p2,NULL);
	
	pthread_mutex_destroy(&mutex);
	pthread_cond_destroy(&cond1);
	pthread_cond_destroy(&cond2);

	return 0;
}