diy2.py

i=3
username = "python"
userpassword = "123456"
while True:
    name = input("请输入用户名:")
    password = input("请输入密码:")
    i-=1
    if i>0:
        if name == username and password == userpassword:
            print("登录成功!")
            break
        if name != username:
            print("用户名不存在")
            continue
        if password != userpassword :
            print("密码不正确")
    else:
        
print("欢迎来到贝尔编程!")