函数基础

# 注册
username = input('username: ').strip()
pwd = input('password: ').strip()

with open('38a.txt', 'a', encoding='utf8') as fa:
    fa.write(f"{username}:{pwd}\n")
    fa.flush()

# 登录
inp_username = input('username: ').strip()
inp_pwd = input('password: ').strip()

with open('38a.txt', 'rt', encoding='utf8') as fr:
    for user_info in fr:
        user_info = user_info.strip('\n')
        user_info_list = user_info.split(':')
        if inp_username == user_info_list[0] and inp_pwd == user_info_list[1]:
            print('login successful')
            break
    else:
        print('failed')

def 函数名(param1、param2……):
    """
    函数功能的描述信息
    :param1：描述
    :param2：描述
    :return：返回值
    """
    code 1
    code 2
    code 3
    ...

    return 返回值

函数名(param1、param2……)

# 注册功能函数
def register():
    """注册功能"""
    username = input('username: ').strip()
    pwd = input('password: ').strip()

    with open('38a.txt', 'a', encoding='utf8') as fa:
        fa.write(f"{username}:{pwd}\n")
        fa.flush()


register()
# 复用
register()
register()

# 登录功能函数
def login():
    """登录功能"""
    inp_username = input('username: ').strip()
    inp_pwd = input('password: ').strip()

    with open('38a.txt', 'rt', encoding='utf8') as fr:
        for user_info in fr:
            user_info = user_info.strip('\n')
            user_info_list = user_info.split(':')
            if inp_username == user_info_list[0] and inp_pwd == user_info_list[1]:
                print('login successful')
                break
        else:
            print('failed')


login()

def func():
    bar()  # 不属于语法错误，不会报错
    print('*'*10)

def bar():
    print('from bar')

def foo():
    print('from foo')
    bar()

foo()
'''
from foo
from bar
'''

def foo():
    print('from foo')
    bar()
    
def bar():
    print('from bar')

foo()
'''
from foo
from bar
'''