实验2.1

@@ -4,30 +4,30 @@
 #include <unistd.h>
 #include <sys/types.h>
 #include <semaphore.h>
-int n=10, in=0,out=0,buffer[10];
-sem_t empty,full;
+int n=10, in=0,out=0,buffer[10];//定义变量并创建数组。
+sem_t empty,full;//定义信号量
 
 void* producer(void *arg){
-    int tag= pthread_self()%100;
+    int tag= pthread_self()%100;//线程信号
     int nextPro;
-    srand(time(NULL)+tag);
+    srand(time(NULL)+tag);//随机数种子
     while(1){
         nextPro = rand()%97;
-        sem_wait(&empty);
+        sem_wait(&empty);//empty–1
         buffer[in] = nextPro;
         printf("production:%d %d\n",nextPro,buffer[in]);
         usleep(1000*1000/20);
         in = (in+1)%n;
-        sem_post(&full);
+        sem_post(&full);//full+1
         usleep(1000*1000/2);
     }
 }
 void* consumer(void *arg)  {
     int item;
     while(1){
-        sem_wait(&full);
+        sem_wait(&full)//full–1
         item = buffer[out];
-        sem_post(&empty);
+        sem_post(&empty);//empty+1
         printf("consume:%d\n",buffer[out]);
         out = (out+1)%n;
         usleep(1000*1000/10);
@@ -35,13 +35,12 @@ void* consumer(void *arg)  {
 }
 int main() {
     pthread_t tid[7];
-    //初始有10个缓冲区 
     sem_init( &empty, 0,10);
-    sem_init( &full, 0,0);
+    sem_init( &full, 0,0);//初始化信号量
     for(int i=0;i<6;i++)
-        pthread_create(&tid[i], NULL, producer, NULL);
-    pthread_create(&tid[6], NULL, consumer, NULL);
+        pthread_create(&tid[i], NULL, producer, NULL);//创建生产者
+    pthread_create(&tid[6], NULL, consumer, NULL);//创建消费者
     for(int i = 0; i<7; i++)
-        pthread_join(tid[i], NULL);
+        pthread_join(tid[i], NULL);//等待线程结束
     printf("main is over\n");
 }