From 3dc58c3a27b3c23123bb70a09348b1c38b8f77eb Mon Sep 17 00:00:00 2001
From: Nazanin Sabri <nazanin.sabrii@gmail.com>
Date: Sun, 5 Aug 2018 14:08:15 +0430
Subject: [PATCH] add lock

---
 Processes/lock.py | 61 +++++++++++++++++++++++++++++++++++++++++++++++
 README.md         |  5 ++++
 2 files changed, 66 insertions(+)
 create mode 100644 Processes/lock.py

diff --git a/Processes/lock.py b/Processes/lock.py
new file mode 100644
index 0000000..afbe5cc
--- /dev/null
+++ b/Processes/lock.py
@@ -0,0 +1,61 @@
+import time 
+import multiprocessing 
+
+def deposit(balance):
+	for i in range(100):
+		time.sleep(0.01)
+		balance.value = balance.value + 1
+
+
+def withdraw(balance):
+	for i in range(100):
+		time.sleep(0.01)
+		balance.value = balance.value - 1
+
+def problem():
+	balance = multiprocessing.Value('i', 200)
+	d = multiprocessing.Process(target=deposit, args=(balance, ))
+	w = multiprocessing.Process(target=withdraw, args=(balance, ))
+
+	d.start()
+	w.start()
+
+	d.join()
+	w.join()
+	# it should print 200 but it does not
+	print("After transactions: ", balance.value)
+
+
+def deposit_solution(balance, lock):
+	for i in range(100):
+		time.sleep(0.01)
+		lock.acquire()
+		balance.value = balance.value + 1
+		lock.release()
+
+
+def withdraw_solution(balance, lock):
+	for i in range(100):
+		time.sleep(0.01)
+		lock.acquire()
+		balance.value = balance.value - 1
+		lock.release()
+
+
+def solution():
+	balance = multiprocessing.Value('i', 200)
+	lock = multiprocessing.Lock()
+	d = multiprocessing.Process(target=deposit_solution, args=(balance, lock))
+	w = multiprocessing.Process(target=withdraw_solution, args=(balance, lock))
+
+	d.start()
+	w.start()
+
+	d.join()
+	w.join()
+	# it should print 200 but it does not
+	print("After transactions: ", balance.value)
+
+if __name__ == '__main__':
+	problem()
+	solution()
\ No newline at end of file
diff --git a/README.md b/README.md
index 102cfaa..37c4c5b 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,9 @@
 # Python Multithreadig and Multiprocessing 
 
+
+I've used this in the <a href="">Wikipedia Crawler</a>, check it out <a href="">here</a> or you can see the code in this repository.<br>
+
+
 here are the resources I used:
 <ul>
 	<li>https://www.youtube.com/playlist?list=PLeo1K3hjS3uub3PRhdoCTY8BxMKSW7RjN</li>
@@ -7,4 +11,5 @@ here are the resources I used:
 	<li>https://tutorialedge.net/python/python-multithreading-tutorial/</li>
 	<li>http://www.bogotobogo.com/python/Multithread/python_multithreading_creating_threads.php</li>
 	<li>https://pymotw.com/2/multiprocessing/basics.html</li>
+	<li>https://www.youtube.com/watch?v=icE6PR19C0Y</li>
 </ul>
\ No newline at end of file