diy2.py

i=3
username = "python"
userpassword = "123456"
whilt True:
    if i>0
        name = input("请输入用户名:")
        password = input("请输入密码:")
        i-=1
        if name ==username and password ==userpassword
            print("登录成功!")
            break
        if name != username:
            print("用户名和密码错误!请重新输入")
            continue
        if password != userpassword:
            print("密码输入有误,请重新输入")
print("欢迎来到贝尔编程!")