#include <stdio.h>   
#include <stdlib.h>   
#include <pthread.h>   
#include <unistd.h>   
#include <sys/types.h>   
#include <semaphore.h>   
int n=10, in=0,out=0,buffer[10];
sem_t empty,full, mutex;
void* producer(void *arg){
    int tag= pthread_self()%100;
    int nextPro;
    srand(time(NULL)+tag);
    for(int i = 0; i < 10; i++){
        nextPro = rand()%97;
        sem_wait(&empty);
        buffer[in] = nextPro;
        printf("production:%d %d\n",nextPro,buffer[in]); 
        usleep(1000*1000/20);
        in = (in+1)%n;
        sem_post(&full);
        usleep(1000*1000/2);
    }
} 
void* consumer(void *arg)  {
    int item;
    for(int i = 1; i < 10; i++){
        sem_wait(&full);
        item = buffer[out];
        sem_post(&empty);
        printf("consume:%d\n",buffer[out]);
        out = (out+1)%n;
        usleep(1000*1000/10);
    }
}
int main()  {  
	pthread_t tid[6];  
    //初始有10个缓冲区
    sem_init( &empty, 0,10);
    sem_init( &full, 0,0);
    //****************一个生产者和一个消费者***********
    //pthread_create(&tid[0], NULL, producer, NULL); 
	//pthread_create(&tid[1], NULL, consumer, NULL);
    //**********************************************
    //***************一个生产者和多个消费者*************
    /*pthread_create(&tid[0], NULL, producer, NULL);
    for(int i = 1; i < 6; i++){//需要互斥变量
        pthread_create(&tid[i], NULL, consumer, NULL);
    }*/
    //*****************************************
    //***************多个生产者和一个消费者*************
    /*pthread_create(&tid[0], NULL, consumer, NULL);
    for(int i = 1; i < 6; i++){//需要互斥变量
        pthread_create(&tid[i], NULL, producer, NULL);
    }*/
    //********************************************
    //************多个生产者和多个消费者******************
    /*for(int i = 0; i < 3; i++){
        pthread_create(&tid[i], NULL, producer, NULL); 
    }
    for(int i = 3; i < 6; i++){
        pthread_create(&tid[i], NULL, consumer, NULL);
    }*/
    //*********************************************** 
	for(int i = 0; i < 6; i++)  
		pthread_join(tid[i], NULL);      
	printf("main is over\n");
    return 0;
}

//第一题
sem_t A, B, C;
void* printA(void* arg){
    for(int i = 0; i < 10; i++){
        sem_wait(&A);
        printf("A\n");
        sem_post(&B);
    }
}
void* printB(void* arg){
    for(int i = 0; i < 10; i++){
        sem_wait(&B);
        printf("B\n");
        sem_post(&C);
    }  
}
void* printC(void* arg){
    for(int i = 0; i < 10; i++){
        sem_wait(&C);
        printf("C\n");
        sem_post(&A);
    } 
}

int main(){
    sem_init(&A, 0, 1);
    sem_init(&B, 0, 0);
    sem_init(&C, 0, 0);
    pthread_t tid[3];
    pthread_create(&tid[0], NULL, printA, NULL);
    pthread_create(&tid[1], NULL, printB, NULL);
    pthread_create(&tid[2], NULL, printC, NULL);
    for(int i = 0; i < 3; i++)  
		pthread_join(tid[i], NULL);
}

//第二题
sem_t A, B, C;
void* printA(void* arg){
    for(int i = 0; i < 30; i++){
        sem_wait(&A);
        printf("A\n");
        sem_post(&B);
    }
}
void* printB(void* arg){
    for(int i = 0; i < 30; i++){
        sem_wait(&B);
        printf("B\n");
        sem_post(&C);
    }  
}
void* printC(void* arg){
    for(int i = 0; i < 30; i++){
        sem_wait(&C);
        printf("C\n");
        sem_post(&A);
    } 
}

int main(){
    sem_init(&A, 0, 3);//信号量改成3即可输出三次
    sem_init(&B, 0, 0);
    sem_init(&C, 0, 0);
    pthread_t tid[3];
    pthread_create(&tid[0], NULL, printA, NULL);
    pthread_create(&tid[1], NULL, printB, NULL);
    pthread_create(&tid[2], NULL, printC, NULL);
    for(int i = 0; i < 3; i++)  
		pthread_join(tid[i], NULL);
    return 0;
}