Char const* str to vector<unsigned int>

char const* str{ "1 2 4 12 5123" };
std::istringstream iss{ str };
std::vector<unsigned int> vct{ std::istream_iterator<unsigned int>{ iss }, {} };
fann_create_standard_array(vct.size(), vct.data());

std::istringstream iss{ str };
std::vector<unsigned int> vct{ std::istream_iterator<unsigned int>{ iss }, {} };

#include <iostream>
#include <iterator>
#include <sstream>
#include <vector>
 
int main()
{
   typedef std::istream_iterator<unsigned int>
       iter_t;
   
   char const* str = "1 2 4 12 5123";
   std::istringstream iss(str);
   std::vector<unsigned int> vct (iter_t(iss), iter_t() );
}

FANN_EXTERNAL struct fann *FANN_API fann_create_standard_array(unsigned int num_layers, const unsigned int *layers);

fann_create_standard_array(vct.size(), &vct.front());

std::vector<unsigned int> vct (iter_t(iss), iter_t() );

std::vector<unsigned int> vct {iter_t{iss}, iter_t{}};

std::vector<unsigned int> vct((iter_t(iss)), iter_t());