python_2

用户登录：

username_ = "suntao"
password_ = "1111"

for i in range(3):
    username = input("username:")
    password = input("password:")

    if username_ == username and password_ == password :
        print("Welcome user to login.......")
        break
    else:
        print("usename or password is wrong!")

else:
    print ("you have tried too many times!")

python_2

原文：https://www.cnblogs.com/taosun/p/11746097.html