Re: how to boost::range_size work?

From:
Thomas Maeder <maeder@glue.ch>
Newsgroups:
comp.lang.c++.moderated
Date:
21 Dec 2006 14:23:08 -0500
Message-ID:
<m2zm9hulco.fsf@glue.ch>
chuchelo@gmail.com writes:

I want to write code like this:

#include <vector>
#include <iostream>


Your program will require <ostream> as well.

#include <iterator>

template<std::size_t N>
std::vector<int> to_vector(const int i[N]) {


The problem is that N is merely a comment (and i a pointer to const
int). If you change the parameter type to a reference type, as in:

std::vector<int> to_vector(const int (&i)[N])

N becomes part of i's type, and the compiler will determine it from
the argument.

    std::vector<int> v;
    v.assign(i,i+N);
    return v;


    return std::vector<int>(i,i+N);

would be simpler. And obviously, if you write such a function, you'd
substitute a typename template parameter for int:

template<typename T, std::size_t N>
std::vector<T> to_vector(T const (&i)[N])
{
  return std::vector<T>(i,i+N);
}

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