For requirements, if you don't understand, before writing code, it is best to make it clear or get out of it, otherwise you have some time.
I don't know what you are writing.
The above and demand variability is two things, he is clearly demanding. Therefore, it is necessary to emphasize how to make a perfect design according to variable demand. XP is a choice. To now, I think myself is something "garbage".
I hope that I will practice myself, avoid designing and writing the software.
What a wonderful thing is originally software.
