Convert Double to string issues

I have a double of unknown length that I need to split at the
decimal.  I thought I would convert it either to a string or a char.
char seems to be the best since it easily lends itself to splitting.
I have a few issues with this theory.  Hard codeing char M[6] works
fine for my test double -0.5  But I would like it to be more
versitile.  The format "%2.2f" works fine with my test data, but that
should also be versitile.


inline void LineSegment::perpBisect(const double m, const Point p)
char M[6] ;
sprintf(M,"%2.2f",m);