Re: vector assign

From:
"Daniel T." <daniel_t@earthlink.net>
Newsgroups:
comp.lang.c++
Date:
Fri, 23 May 2008 19:44:42 -0400
Message-ID:
<daniel_t-31F69F.19444223052008@earthlink.vsrv-sjc.supernews.net>
In article
<252d0788-1081-441b-b4b6-d3879ccc03cf@k37g2000hsf.googlegroups.com>,
 Dar?o Griffo <dario.griffo.listas@gmail.com> wrote:

stephen b wrote:

it would make for much more readable code that is faster to write in
some situations. I've not seen this feature documented anywhere
though which I find curious. is there another way to achieve this?


Maybe using variable arguments and inheritance

#include <iostream>
#include <vector>
#include <stdarg.h>
#include <iterator>

template <typename T > class myVec: public std::vector<T>
{
    public:
        void assign(int amount,...);
};

template <typename T > void myVec<T>::assign(int amount,...)
{
    T val;
    va_list vl;
    va_start(vl,amount);
    for (int i=0;i<amount;i++)
    {
        val=va_arg(vl,T);
        push_back(val);
    }
    va_end(vl);
}

int main()
{

    myVec<int> vec;
    vec.assign(3,2,1,0);
    std::copy(vec.begin(),vec.end(),std::ostream_iterator<int>(std::cout,
" "));
    return 0;
}

Dar?o


Would this work for non-POD types? BTW inheritance is not necessary.

   template < typename T >
void assign( std::vector<T>& vec, int count, ... )
{
   va_list vl;
   va_start( vl, count );
   for ( int i=0; i!= count; ++i)
   {
      vec.push_back( va_arg( vl, T ) );
   }
   va_end(vl);
}

using namespace std;

int main()
{
   vector<int> vec;
   assign( vec, 3, 2, 1, 0 );
   copy( vec.begin(), vec.end(), ostream_iterator<int>( cout, " " ) );
}

}

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