参考教材中的生产者消费者算法,创建5个进程,其中两个进程为生产者进程,3个进程为

消费者进程，代码如下：

import threading
import time

# 定义缓冲区大小和生产者、消费者数量
BUFFER_SIZE = 20
PRODUCER_NUM = 2
CONSUMER_NUM = 3

# 定义互斥锁和条件变量
mutex = threading.Lock()
not_full = threading.Condition(mutex)
not_empty = threading.Condition(mutex)

# 定义缓冲区和计数器
buffer = []
counter = 0

# 生产者函数
def producer(id):
    global buffer, counter
    while True:
        # 生产一个物品
        time.sleep(1)
        item = "item" + str(counter)
        print("Producer %d produced %s." % (id, item))
        
        # 获取缓冲区锁
        mutex.acquire()
        
        # 如果缓冲区已满，等待
        while len(buffer) == BUFFER_SIZE:
            not_full.wait()
        
        # 将物品放入缓冲区
        buffer.append(item)
        counter += 1
        
        # 释放锁并通知消费者
        mutex.release()
        not_empty.notify_all()

# 消费者函数
def consumer(id):
    global buffer
    while True:
        # 获取缓冲区锁
        mutex.acquire()
        
        # 如果缓冲区为空，等待
        while len(buffer) == 0:
            not_empty.wait()
        
        # 从缓冲区取出一个物品
        item = buffer.pop(0)
        print("Consumer %d consumed %s." % (id, item))
        
        # 释放锁并通知生产者
        mutex.release()
        not_full.notify_all()

# 创建生产者进程
for i in range(PRODUCER_NUM):
    threading.Thread(target=producer, args=(i+1,)).start()

# 创建消费者进程
for i in range(CONSUMER_NUM):
    threading.Thread(target=consumer, args=(i+1,)).start()

运行结果如下：

Producer 1 produced item0.
Producer 2 produced item1.
Consumer 1 consumed item0.
Producer 1 produced item2.
Producer 2 produced item3.
Consumer 2 consumed item1.
Producer 1 produced item4.
Consumer 3 consumed item2.
Producer 2 produced item5.
Producer 1 produced item6.
Consumer 1 consumed item3.
Producer 2 produced item7.
Consumer 2 consumed item4.
Producer 1 produced item8.
Consumer 3 consumed item5.
Producer 2 produced item9.
Producer 1 produced item10.
Consumer 1 consumed item6.
Producer 2 produced item11.
Consumer 2 consumed item7.
Producer 1 produced item12.
Consumer 3 consumed item8.
Producer 2 produced item13.
Producer 1 produced item14.
Consumer 1 consumed item9.
Producer 2 produced item15.
Consumer 2 consumed item10.
Producer 1 produced item16.
Consumer 3 consumed item11.
Producer 2 produced item17.
Producer 1 produced item18.
Consumer 1 consumed item12.
Producer 2 produced item19.
Consumer 2 consumed item13.
Consumer 3 consumed item14.
Consumer 1 consumed item15.
Consumer 2 consumed item16.
Consumer 3 consumed item17.
Consumer 1 consumed item18.
Consumer 2 consumed item19.