Question

PLEASE DO NOT COPY CODE FROM OTHER QUESTIONS POSTED WITH THIS. THAT IS C++ NOT PYTHON

Please follow the step below.

1. You need to develop a multithread program in PYTHON to simulate a checkout in supermarket. The process of simulation will last for T1 seconds. You do not need to consider thread safety.

2. An integer sequence t is used to record the remaining waiting time for each customer.

3. One thread which runs every one second is used to simulate the processing of the checkout. (a) Reduce the remaining processing time of the first customer by one. (b) Remove the first customer if his remaining processing time reaches zero. (c) Clean the screen and show the new remaining processing time.

4. Another thread is used to generate one new customer every T2 seconds. (a) The new customer will leave the supermarket if he or she needs to join a queue with more than R customers. (b) The processing time for the new customer is a random integer in [Tmin; Tmax)

5. An example program run is shown as follows.

Checkout: 3 12 45 5 61, after one second, we have:

Checkout: 2 12 45 5 61, after one second, we have:

Checkout: 1 12 45 5 61 22, after one second, we have:

Checkout: 12 45 5 61 22, after one second, we have:

Checkout: 11 45 5 61 22

Answer 1

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• Note: for windows users
• USE os.system('cls') instead of os.system('clear')

SOLUTION:

Code in Python3 ThreadQueueHandle.py

CODE(Be careful with indentation):

#!/usr/bin/python3

import threading

import time

import random

import os

exitFlag = 0

t=[6,5,7,3,8]

Tmin=1

Tmax=8

R=5

T1=20

T2=8

tsec=0

class myThread (threading.Thread):

def __init__(self, threadID,delay):

threading.Thread.__init__(self)

self.threadID = threadID

self.delay = delay

def run(self):

if self.threadID == 1:

inc_time(self.delay)

else:

add_customer()

def inc_time(delay):

global t,T1,tsec

while t!=[] and tsec<=T1:

if exitFlag:

threadName.exit()

time.sleep(delay)

os.system('clear')

print("Checkout: "+" ".join(map(str,t))+", after one second, we have")

t[0] -= 1

tsec+=1

if t[0]==0:

t.pop(0)

def add_customer():

global t,tsec,T2

flag=1

while t!=[] and tsec<=T1:

if tsec and tsec%T2==0:

if flag:

t.append(random.randrange(Tmin,Tmax))

flag=0

else:

flag=1

# Create new threads

thread1 = myThread(1,1)

thread2 = myThread(2,1)

# Start new Threads

thread1.start()

thread2.start()

thread1.join()

thread2.join()

SAMPLE I/O:

Checkout: 6 5 7 3 8, after one second, we have
Checkout: 5 5 7 3 8, after one second, we have
Checkout: 4 5 7 3 8, after one second, we have
Checkout: 3 5 7 3 8, after one second, we have
Checkout: 2 5 7 3 8, after one second, we have
Checkout: 1 5 7 3 8, after one second, we have
Checkout: 5 7 3 8, after one second, we have
Checkout: 4 7 3 8, after one second, we have
Checkout: 3 7 3 8 1, after one second, we have
Checkout: 2 7 3 8 1, after one second, we have
Checkout: 1 7 3 8 1, after one second, we have
Checkout: 7 3 8 1, after one second, we have
Checkout: 6 3 8 1, after one second, we have
Checkout: 5 3 8 1, after one second, we have
Checkout: 4 3 8 1, after one second, we have
Checkout: 3 3 8 1, after one second, we have
Checkout: 2 3 8 1 2, after one second, we have
Checkout: 1 3 8 1 2, after one second, we have
Checkout: 3 8 1 2, after one second, we have
Checkout: 2 8 1 2, after one second, we have
Checkout: 1 8 1 2, after one second, we have