# _*_ coding:utf-8 _*_

'''
没有lock的例子
'''
import time, threading
# 假定这是你的银行存款:
balance = 0
def change_it(n):
    # 先存后取,结果应该为0:
    global balance
    balance = balance + n
    balance = balance - n
def run_thread(n):
    for i in range(100000):
        change_it(n)
t1 = threading.Thread(target=run_thread, args=(5,))
t2 = threading.Thread(target=run_thread, args=(8,))
t1.start()
t2.start()
t1.join()
t2.join()
print balance