#include <cassert>
#include <iostream>
#include <iterator>
#include <set>
#include <sstream>
#include <string>
#include <vector>

namespace details
{

    void read(std::istream& is, std::string& out, int, int)
    {
        std::getline(is, out);
    }
    
    template <typename T>
    auto read(std::istream& is, T& out, int, int)
        -> decltype( out.push_back( typename T::value_type{} ), std::declval<void>() )
    {
        typename T::value_type element { };
        while (is >> element)
        {
            out.push_back(element);
        }
    }

    template <typename T>
    auto read(std::istream& is, T& out, int, float)
        -> decltype( out.insert(std::end(out), typename T::value_type{} ), std::declval<void>() )
    {
        typename T::value_type element { };
        while (is >> element)
        {
            out.insert(std::end(out), element);
        }
    }

    template <typename T>
    void read(std::istream& is, T& out, float, float)
    {
        is >> out;
    }
    
}

template <typename T>
void read(std::istream& is, T& out)
{
    return details::read(is, out, 0, 0);
}

int main()
{
    {
        int value { };
        
        std::istringstream iss { "37 38 39" };
        read(iss, value);
        assert( value == 37 );
    }

    {
        std::string value { };
        
        std::istringstream iss { "a test line" };
        read(iss, value);
        assert( value == "a test line" );
    }

    {
        std::set<char> value { };
        
        std::istringstream iss { "cba" };
        read(iss, value);
        assert(( value == std::set<char>{ 'a', 'b', 'c' } ));
    }
    
    {
        std::vector<int> value { };
        
        std::istringstream iss { "1 4 2 3" };
        read(iss, value);
        assert(( value == std::vector<int>{ 1, 4, 2, 3 } ));
    }    
}