import threading
from threading import Thread
from threading import Condition
import time
import random
 
c = Condition()  # 條件鎖
itemNum = 0
item = 0
 
def consumer():  # 消費者
    global item  # 商品編號
    global itemNum
    c.acquire()  # 鎖住資源
    while 0 == itemNum:  # 如無產品則讓執行緒等待
        print(
 
"consumer :掛起.", threading.current_thread().name, threading.current_thread())
        c.wait()
    itemNum -= 1
    print("consumer : 消費 %s." % item, itemNum, threading.current_thread().name, threading.current_thread())
    c.release()  # 解鎖資源
 
def producer():  # 生產者
    global item  # 商品編號
    global
 
 itemNum
    time.sleep(3)
    c.acquire()  # 鎖住資源
    item = random.randint(1, 1000)
    itemNum += 1
    print("producer : 生產 %s." % item, threading.current_thread().name, threading.current_thread())
    c.notifyAll()  # 喚醒所有等待的執行緒--》其實就是喚醒消費者程序
    c.release()  # 解鎖資源
 
threads = []  # 執行緒收集列表
 
for
 
 i in range(0, 4):  # 使用迴圈完成生產者與消費者執行緒的建立
    t1 = Thread(target=producer, name=f'pro_{i}')
    t2 = Thread(target=consumer, name=f"cos_{i}")
    t1.start()
    t2.start()
    threads.append(t1)
    threads.append(t2)
 
for t in threads:  # 等待所有執行緒完成
    t.join()