From:

Le Chaud Lapin <jaibuduvin@gmail.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Wed, 21 Jan 2009 12:54:49 CST

Message-ID:

<7aa5a205-931b-419b-a7fc-a6af843cad2b@n41g2000yqh.googlegroups.com>

On 14 jan, 01:19, Le Chaud Lapin <jaibudu...@gmail.com> wrote:

Why not throw directly from Integer::divide?

You could also return a tuple (here, a pair) rather than taking

objects to modify by reference.

This would likely result in more efficient code, for a number of

reasons.

Here is example of big-integer division code that could be buried deep

within a cryptographic operation:

Integer operator / (const Integer ÷nd, const Integer &divisor)

{

Integer quotient, remainder;

if (!Integer::divide (dividend, divisor, quotient, remainder))

throw Integer::DIVISION_BY_ZERO;

return quotient;

}

Integer::divide() returns true for success, false for failure, but

operator / would lose all its beauty if it had to return an error:

within a cryptographic operation:

Integer operator / (const Integer ÷nd, const Integer &divisor)

{

Integer quotient, remainder;

if (!Integer::divide (dividend, divisor, quotient, remainder))

throw Integer::DIVISION_BY_ZERO;

return quotient;

}

Integer::divide() returns true for success, false for failure, but

operator / would lose all its beauty if it had to return an error:

Why not throw directly from Integer::divide?

You could also return a tuple (here, a pair) rather than taking

objects to modify by reference.

This would likely result in more efficient code, for a number of

reasons.

Hmm...I thought I had a reason, but after checking and rechecking my

Integer.cpp file, I cannot find one, so thanks...I will do just

that. :)

For example,

millions, if not billions, of lines of C++ have been written, and we

still do not have obviously fundamental classes like hierarchies and

associative hierarchies.

millions, if not billions, of lines of C++ have been written, and we

still do not have obviously fundamental classes like hierarchies and

associative hierarchies.

A recursive variant might provide the kind of thing you're looking

for. See Boost.Variant.

This is usually how trees are handled in high-level languages, be it

functional ones (where the variant is explicit) or dynamic ones (where

the variant is implicit, it's the dynamic typing).

I have several templated hierarchy classes, with operations and O(n)

that one would reasonable expect: not spectactular, but O[log(n)]

where it matters.

Property trees are also a nice way to deal with trees. (You associate

a path in a tree with a value, quite useful for hierarchical

configuration files)

You might want to look at Boost.PropertyTree.

a path in a tree with a value, quite useful for hierarchical

configuration files)

You might want to look at Boost.PropertyTree.

That would be...

typedef Associative_Monarchy<String<>, Associative_Set<String<>,

String<> > > PropertyTree;

PropertyTree::Path path;

.... in the my model.

I agree that one can get very close to XML-like internal data

structures very quickly with these types of containers.

And the reachability provide by combining such primitives, along with

the regular list<>, set<>, map<>, etc., is staggering.

-Le Chaud Lapin-

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