Anonymous wrote:

> I ahve a vector of doubles taht I need to extract values from. I was
> just about to use the STL find() algo, but I have a couple of questions:
>
> first: can you specify the tolerance threshold to match on doubles?
> second: if yes, how may this be done (i.e. how many one specify the
> tolerance threshold for comparing doubles?)

Note that find() has two signatures: one that takes a value to be found and
one that takes a unary predicate instead. Use the later and provide a
functor:

class is_approximately {

double x;

public:

is_approximately ( double what )
: x ( what )
{}

bool operator() ( double y ) const {
// return true if y is near x.
}

};

Now you can do:

find( whatever.begin(), whatever.end(), is_approximately( 0.5 ) );



Best

Kai-Uwe Bux