7.多线程---全局变量---共享全局变量

#多线程---全局变量---共享全局变量
#多线程可以对全局变量进行修改,修改后的结果会影响下一个线程
#进程不可以共享全局变量,子进程是复制父进程的全局变量,修改后互不影响
from threading import Thread
import time,random
g_num = 100

def work1():
    global g_num
    for i in range(3):
        g_num += 1
        time.sleep(random.random())
        print("in work1,g_num=%d"%g_num)

def work2():
    global g_num
    for i in range(3):
        g_num += 1
        time.sleep(random.random())
        print("in work2,g_num=%d"%g_num)

if __name__ == "__main__":
    # work1()
    # work2()
    # print("主线程g_num%d"%g_num)

    t1 = Thread(target=work1)
    t2 = Thread(target=work2)
    t1.start()
    t2.start()

    # print("主线程g_num%d" % g_num)