11.24实战

需求：注册，登录

def out():
    username=input("输入账号:\n")
    password=input("输入密码:\n")
    return username,password
def register():
    username,password=out()
    a=username+" "+password
    f=open("user.txt","w")
    f.write(a)
    f.close()
def logon():
    username,password=out()
    f=open("user.txt","r")
    list1=f.read().split(" ")
    if username==list1[0] and password==list1[1]:
        print("登录成功")
    else:
        print("登录失败")

if __name__ == '__main__':
    while True:
        a=int(input("1.注册 2.登录 3.退出\n"))
        if a==1:
            register()
        elif a==2:
            logon()
        elif a==3:
            break