diy2.py

i=3
username = "python"
userpassword = "123456"
while True:
    if i>0:
        name = input("请输入用户名:")
        password = input("请输入密码:")
        i=i-1
        if name == username and password == userpassword:
            print("登录成功!")
            break
        if username != name:
            print("用户名错误!请重新输入")
            continue
        if userpassword != password:
            print("密码错误！请重新登录")
            continue
    else: 
        print("登录次数用完")
        exit()
print("欢迎来到贝尔编程!")