High precision floating point arithmatic in C++

One of my friens had a need for a floating point type that would allow a precision level upto 9 decimal points. "long double" would have been our choice if not for the differences in implementation and VC++ not supporting it (in VC++, long double = double).

We opted for doubledouble which has a precision level upto 30 decimal points.

Some other options are available here.