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 
        if  name != username:
            print("账号错误!") 
            continue  
        if  password == userpassword:
            print("密码错误!")
    else:
         print("账号已锁定")  
         exit()     
print("欢迎来到贝尔编程!")