diy2.py

username = "python"
userpassword = "123456"
i=3
while 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
        elif name != username:
            print("用户名错误，请重新输入！")
        elif password != username:
            print("密码错误，请重新输入！")
    else:
        print("错误次数过多账号已被锁定！")
        exit()
print("欢迎来到贝尔编程!")