diff --git a/README.md b/README.md
index 5ff9643..0c669ac 100644
--- a/README.md
+++ b/README.md
@@ -58,3 +58,152 @@ int main()
 	}
 	printf("main is over\n");
 }
+
+
+#include <stdio.h>
+#include <stdlib.h>//for exit()
+#include <pthread.h>//for pthread()
+#include <unistd.h> //for fork()and execl()
+#include <sys/types.h>
+#include <semaphore.h>//for sem_wait()and sem_post()
+
+int n=10,in=0,out=0,buffer[10];         //global variables:buffer   sem_t defines signal and two signal inited in main
+//n用作取模，in和out分别当作生产者的放和消费者的取,buffer[10]代表十个缓冲区，可同时读和写
+sem_t empty,full;       //当库存为空时，消费者不再拿。当库存为满时，生产者不再生产。
+
+void* producer(void*arg)
+{
+    int tag=pthread_self()%100;         //线程id的模，可重复
+        int nextPro;            //用作输出当前线程产品名
+        srand(time(NULL)+tag);          //pthread_self(): thread number         Srand: rand seed;
+        // one producer produces constantly
+        while(1)
+        {
+                nextPro=rand()%97;
+                sem_wait(&empty);
+                buffer[in]=nextPro;
+                printf("production:%d %d\n",nextPro,buffer[in]);        //buffer[in]可能在多线程中发生冲突而改变
+				usleep(1000*1000/20);   //sleep: unit is weimiao;       1 seconds = 1000*1000 weimiao,except 20 equal to 0.05 seconds;
+                in=(in+1)%n;
+                sem_post(&full);        //wait and signal of signmount
+                usleep(1000*1000/2);
+        }
+}
+//consumer process
+void* consumer(void *arg)
+{
+        int item;
+        while(1)
+        {
+                sem_wait(&full);
+                item = buffer[out];
+                sem_post(&empty);
+                printf("consume:%d\n",buffer[out]);
+                out=(out+1)%n;
+				usleep(1000*1000/2);
+        }
+}
+
+int main()
+{
+        pthread_t tid[7];
+        //初始有10个缓冲区
+        //线程号数组：根据需要，有多少线程，就定位多大
+        sem_init(&empty,0,10);  //整形信号量初始化函数：第3个参数表示信号量的初始值，第2个参数可暂时不管
+        sem_init(&full,0,0);
+        for(int i=0;i<6;i++)
+        {
+                pthread_create(&tid[i],NULL,producer,NULL);                     //create thread
+        }
+        pthread_create(&tid[6],NULL,consumer,NULL);
+        for(int i=0;i<7;i++)
+        {
+                pthread_join(tid[i],NULL);      //等待所有线程结束，若不然，main结束后其他线程将被终止
+        }
+        printf("main is over\n");
+}       
+
+	#include<stdio.h>//for printf()
+	#include<stdlib.h>//for exit()
+	#include<pthread.h>//for thread()
+	#include<unistd.h>// for fork()and execl()
+	#include<sys/types.h>
+	#include<semaphore.h>// for signal() and wait()
+	//order by A,B,C
+	//thread order by p1,p2,p3
+	//when p1 printf A wait p3 printf C
+	//order by A,A,A B,B,B C,C,C
+	//thread order by p1 3 times,p2 3 times,p3 times
+	//when p1 printf A wait 3 times,printf B wait 3 times,printf C wait 3 times;
+	//sem_t a,b,c,add;
+	sem_t a,b,c;
+	void* p1(void *arg)
+	{
+			for(int i=0;i<10;i++)
+			{
+			//      sem_wait(&a);   //a sign first ,add sign follow
+			//      if(i%3==0)      //when printf A first time wait
+			//      {
+			//              sem_wait(&add);
+			//      }
+					sem_wait(&a);
+					printf("A\n");
+                sem_post(&b);
+        //      if(i%3==2)      //when printf A last time signal
+        //      {
+        //              sem_post(&add);
+        //      }
+        }
+}
+void* p2(void *arg)
+{
+        for(int i=0;i<10;i++)
+        {
+        //      sem_wait(&b);
+        //      if(i%3==0)
+        //      {
+        //              sem_wait(&add);
+        //      }
+                sem_wait(&b);
+                printf("B\n");
+                sem_post(&c);
+        //      if(i%3==2)
+        //      {
+        //              sem_post(&add);
+		//      }
+        }
+}
+void* p3(void *arg)
+{
+        for(int i=0;i<10;i++)
+        {
+        //      sem_wait(&c);
+        //      if(i%3==0)
+        //      {
+        //              sem_wait(&add);
+        //      }
+                sem_wait(&c);
+                printf("C\n");
+                sem_post(&a);
+        //      if(i%3==2)
+        //      {
+        //              sem_post(&add);
+        //      }
+        }
+}
+int main()
+{
+        pthread_t tid[3];
+        sem_init(&a,0,1);
+        sem_init(&b,0,0);
+        sem_init(&c,0,0);
+//      sem_init(&add,0,1);
+        pthread_create(&tid[0],NULL,p1,NULL);
+        pthread_create(&tid[1],NULL,p2,NULL);
+        pthread_create(&tid[2],NULL,p3,NULL);
+        for(int i=0;i<3;i++)
+        {
+                pthread_join(tid[i],NULL);
+        }
+        printf("main is over\n");
+}
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