20.03.19作业

作业要求：下述所有代码画图以及分析代码执行流程

1、以定义阶段为准，先画出名称空间的嵌套关系图

2、然后找到调用函数的位置，写出函数调用时代码的执行过程，涉及到名字的查找时，参照1中画好

的嵌套图，标明查找顺序，一层一层直到找到位置

===================题目一===================

input=333
def func():
    input=444
func()
print(input)

===================题目二===================

def func():
    print(x)
x=111

func()

===================题目三===================

x=1
def func():
   print(x)

def foo():
    x=222
    func()

foo()

===================题目四===================

input=111
def f1():
    def f2():
        # input=333
        print(input)
    input=222

f2()

f1()

===================题目五===================

x=111
def func():
    print(x) #
    x=222

func()

===================题目六===================

x=111

def foo():
    print(x,)

def bar():
    print(x)

foo()
bar()

===================题目七===================

x=1
def func2():
    func1()

x=2
def func1():
    print(x)

x=3

func2()

===================题目八===================

1、如下全局变量记录了当前登录用户，编写登录功能，一旦用户登录成功，
则将全局变量赋值为当前登录的用户名
login_user=None
2、针对之前编写的查询余额的功能，添加额外的逻辑：如果用户没有登录，则先执行登录功能

login_user=None
def login():
    username = input('请输入用户名: ').strip()
    password = input('请输入密码: ').strip()
    if username == 'tank' and password == '123':
        global login_user
        login_user = username
        print('登录成功!')
    else:
        print('登录失败!')
def check_money(username):
    if login_user == None:
        login()
    dic = {}
    with open('db3.txt', 'r', encoding='utf-8') as f:
        for line in f:
            user, money = line.strip().split(':')
            dic[user] = int(money)

    if username not in dic:
        return
    return dic.get(username)
while 1:
    username = input('name')
    print(check_money(username))