Re: I'd like to use STL algorithms

From:

Ulrich Eckhardt <eckhardt@satorlaser.com>

Newsgroups:

comp.lang.c++.moderated

Date:

20 Sep 2006 11:40:03 -0400

Message-ID:

<ke57u3-v7c.ln1@satorlaser.homedns.org>

imbunche wrote:

The following code applys a conversion function to elements on a vector
depending on its index,

^^^^^^^^^^^^^^^^^^^^^^^ this is the problem!

as follows:

int i;
vector<sometype> val;
for (i=0; i<tokens.size(); ++i)
{
val[i] = convert(i,v[i]);
// or ... val.push_back(convert(i,v[i]));
}

The best I have achieved (with my limited STL knowledge is:
transform(tokens.begin(), tokens.end(),
back_inserter(val), // where to put results.
bind (convert,
0, _1));
Which is useless of course becauss it fixes the first parameter of
convert to 0, ... I need some kind of i++ but I cannot find the way
....

The point is that this is not a single conversion but many different
ones, because they depend on the position of the element inside the vector.
Sorry, but I think that the algorithms of the stdlibrary are simply not
the right tool here. I also couldn't think of a way to express it
stdlibrary-like, as it typically deals with sequences that are mostly
not even accessible via an index.

Uli

[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]