jungx148:
I am having a trouble demonstrating the writing temperature values in a text file saved in SD card.
It would help if you properly explained what actually happens. Do you see any of the serial.prints, and if so which?
Assuming you have properly edited the SD library and the SD is properly identified, have you properly formatted the SD? There is a sticky about this at the head of the forum. I believe Arduino can see and identify a card that isn't kosher, but still not be able to write to it.