Iteration through the decimal part of a double?

Question

I have a double a = 123.123456
I need a program that outputs 123456.
Edit: Not output, but to store the digits in a char array.

Answer 1

I've written this program but the output is far from being the needed one.
http://www.sololearn.com/app/cplusplus/playground/cVdfGaY4IEXh/

Answer 2

http://www.sololearn.com/app/cplusplus/playground/c83sz3Wbx4Kx/

Answer 3

The goal here is to be able to convert it into char array.

Answer 4

Float f = 123.123456;
Int I = f;
Cout << f - I;