编写一个程序，开启3个线程，这3个线程的ID分别为A、B、C，每个线程将自己的ID在屏幕上打印10遍，要求输出结果必须按ABC的顺序显示；如：ABCABC….依次递推。
程序代码如下:
#include
#include
using namespace std;
#ifdef __cplusplus
extern "C"
{
#endif
#include
#include
#ifdef __cplusplus
}
#endif
sem_t sem1,sem2,sem3;
int var = 1;
void *PrintA(void *ptr)
{
int i;
for(i = 0;
i < 10;
i++)
{
sem_wait(&sem1);
cout<<"A";
sem_post(&sem2);
}
return NULL;
}
void *PrintB(void *ptr)
{
for(int i = 0;
i < 10;
i++)
{
sem_wait(&sem2);
cout<<"B";
sem_post(&sem3);
}
return NULL;
}
void *PrintC(void *ptr)
{
for(int i = 0;
i < 10;
i++)
{
sem_wait(&sem3);
cout<<"C";
sem_post(&sem1);
}
return NULL;
}
void init_thread()
{
int rc1,rc2,rc3;
pthread_t thread1,thread2,thread3;
sem_init(&sem1,0,0);
sem_init(&sem2,0,0);
sem_init(&sem3,0,0);
if( (rc1 = pthread_create(&thread1,NULL,PrintA,NULL) ))
{
cout<<"create thread is failed"<
}
if( (rc2 = pthread_create(&thread2,NULL,PrintB,NULL) ))
{
cout<<"create thread is failed"<
}
if( (rc3 = pthread_create(&thread3,NULL,PrintC,NULL) ))
{
cout<<"create thread is failed"<
}
sem_post(&sem1);
pthread_join(thread1,NULL);
pthread_join(thread2,NULL);
pthread_join(thread3,NULL);
}
int main(int argc,char *argv[])
{
init_thread();
cout<
}
方法二
#include
#include
#include
#include
pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
int k = 0;
void* rountine_A(void* arg)
{
int i;
char ch = (int)arg;
pthread_detach(pthread_self());
for(i=0;
i<10;
++i) {
//printf("A1 thread is going\n");
pthread_mutex_lock(&mutex);
//printf("A2 thread is going\n");
while('A'==ch && k!=0) {
//printf("A3 thread is going\n");
pthread_cond_wait(&cond,&mutex);
//printf("A4 thread is going\n");
}
printf("%c\n",ch);
fflush(stdout);
k = (k+1)%3;
pthread_cond_broadcast(&cond);
pthread_mutex_unlock(&mutex);
}
return (void*)0;
}
void* rountine_B(void* arg)
{
int i;
char ch = (int)arg;
pthread_detach(pthread_self());
for(i=0;
i<10;
++i) {
//printf("B1 thread is going\n");
pthread_mutex_lock(&mutex);
//printf("B2 thread is going\n");
while('B'==ch && k!=1){
//printf("B3 thread is going\n");
pthread_cond_wait(&cond,&mutex);
//printf("B4 thread is going\n");
}
printf("%c\n",ch);
fflush(stdout);
k = (k+1)%3;
pthread_cond_broadcast(&cond);
pthread_mutex_unlock(&mutex);
}
return (void*)0;
}
void* rountine_C(void* arg)
{
int i;
char ch = (int)arg;
pthread_detach(pthread_self());
for(i=0;
i<10;
++i) {
//printf("C1 thread is going\n");
pthread_mutex_lock(&mutex);
//printf("C2 thread is going\n");
while('C'==ch && k!=2) {
//printf("C3 thread is going\n");
pthread_cond_wait(&cond,&mutex);
//printf("C4 thread is going\n");
}
printf("%c\n",ch);
fflush(stdout);
k = (k+1)%3;
pthread_cond_broadcast(&cond);
pthread_mutex_unlock(&mutex);
}
return (void*)0;
}
int main(void)
{
pthread_t tid[3];
pthread_create(&tid[0],NULL,rountine_A,(void*)('A'));
pthread_create(&tid[1],NULL,rountine_B,(void*)('B'));
pthread_create(&tid[2],NULL,rountine_C,(void*)('C'));
sleep(1);
printf("\n");
return 0;
}
【线程顺序打印ABC】
