while.py

i=5
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-=1
        if name==username and password==userpassword:
            print("登录成功")
            break
        if name!=username:
            print("用户名错误")
            print("还剩"+str(i)+"机会")
            continue
        if password!=userpassword:
            print("密码错误")
            print("还剩"+str(i)+"机会")
    else:
        print("密码锁定")
        exit()
print("欢迎进入")