Re: I'd like to use STL algorithms
Vladimir Marko wrote:
imbunche wrote:
The following code applys a conversion function to elements
on a vector depending on its index, 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
....
You need the boost::counting_iterator and the second overload
of transform:
std::transform(
tokens.begin(),tokens.end(), // first1, last1
boost::counting_iterator<std::size_t>(0u), // first2
tokens.begin(), // result
boost::bind(convert,_2,_1) // binary_op
//< in which namespace are _1 and _2? Never mind.
);
See http://www.boost.org/libs/iterator/doc/counting_iterator.html .
Clever but... doesn't this sort of hide the fact that the
transformation done to each element is a function of the
numeric value of its index in the array? And as such, count as
obfuscation?
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