diy.py

username = "python"
userpassword = "123456"
i=3
while True:
    if i>0:
        name = input("请输入用户名:")
        #if name!=username:
        #   print("用户名不存在，请重新输入！")
        #  continue
        password = input("请输入密码:")
        i=i-1
        #if name == username and password == userpassword:
        #   print("登录成功!")
        #  break
        
        #if password!=userpassword:
        #   print("密码输入有误，请重新输入！")
        if name==username and password==userpassword:
            print("登陆成功")
        elif name==username and password!=userpassword:
            print("密码输入错误")
        else:
            print("账号输入错误")
    else:
        print("你的账户已被锁定，请带身份证老我司解锁")
        exit()      
print("欢迎来到贝尔编程!")