03.5 使用多線程完成從0加到1000

#include<stdio.h>
#include<pthread.h>
#define N 1000
void* thread_main(void *arg);
//void printids(const char *s);
int	sum = 0;
int j = 0;

int main(int argc, char *argv[]) {
	pthread_t t1_id, t2_id;
	int thread_param = 5;
	int k = 0;
	int zsum = 0;

	if (pthread_create(&t1_id, NULL, thread_main, (void*)&thread_param) != 0) {
		puts("pthread_create() error1");
		return -1;
	};
	if (pthread_create(&t2_id, NULL, thread_main, (void*)&thread_param) != 0) {
		puts("pthread_create() error2");
		return -1;
	};
	pthread_join(t1_id, NULL);
	pthread_join(t2_id, NULL);

	//sleep(10); puts("end of main");
	//主線程運行累加
	while (1) {
		zsum += ++k;
		//printf("k = %d, zsum = %d\n", k, zsum);
		if (k == N)
			break;
	}
	printf("sum = %d\n", sum);
	printf("zsum = %d\n", zsum);
	return 0;
}

//運行線程
void* thread_main(void *arg) {
	/*int i;
	int cnt = *((int*)arg);
	for (i = 0; i < cnt; i++) {
		sleep(1); puts("running thread");
	}*/
	while (1) {
		if (j >= N) {
			break;
		}
		sum += ++j;
		printf("j = %d, sum = %d\n",j, sum);
		
	}	
	
	return NULL;
}

/*void printids(const char *s)
{
	pid_t pid;
	pthread_t tid;
	pid = getpid();
	tid = pthread_self();
	printf("%s pid %u tid %u (0x%x)\n", \
		s, (unsigned int)pid, (unsigned int)tid, (unsigned int)tid);
}*/