How to get non-pre-determined inputs from console?

From: Zuan Chen (cyberpsyche_at_163.com)
Date: 06/30/04


Date: 30 Jun 2004 20:06:47 +0000

A program should read a series of inputs from console, but the number of
series is not pre-determined.

Sample input:
1 2
3 4
100 200
500 600
...

The Input may terminated by "\n\n".
I want to use scanf() function to read the input, but I cannot write the right
code.

Can anybody give me a hand???
Thanks for any help!