if else 用户名密码判断
username="alex"
_password="123"
name=input("name:")
password=input("password:")
if name==username and password==_password:
print("welcome the new word {name}".format(name=username))
else:
print("滚")
username="alex"
_password="123"
name=input("name:")
password=input("password:")
if name==username and password==_password:
print("welcome the new word {name}".format(name=username))
else:
print("滚")