Untitled

Print vector of vectors to ostream

#include <iterator>

#include <iostream>

#include <string>

#include <vector>

#include <algorithm>

 

template<typename T>

std::ostream &operator <<(std::ostream &os, const std::vector<T> &v) {

    using namespace std;

    copy(v.begin(), v.end(), ostream_iterator<T>(os, "n"));

    return os;

}

 

int main() {

    using namespace std;

    vector<string> v1;

    cout << v1;

    vector<vector<string> > v2;

    cout << v2;

    return 0;

}

       

error: cannot bind 'std::ostream_iterator<std::vector<std::basic_string<char> >, char, std::char_traits<char> >::ostream_type {aka std::basic_ostream<char>}' lvalue to 'std::basic_ostream<char>&&'

       

error: no match for 'operator<<' in '*((std::ostream_iterator<std::vector<std::basic_string<char> >, char, std::char_traits<char> >*)this)->std::ostream_iterator<std::vector<std::basic_string<char> >, char, std::char_traits<char> >::_M_stream << __value'

       

void fun(int);

 

namespace Test {

 

  void fun() { fun(3); }

 

}

 

int main() {

    Test::fun();

}

       

template<typename T>

std::ostream &operator <<(std::ostream &os, const std::vector<T> &v) {

   using namespace std;

   copy(v.begin(), v.end(), ostream_iterator<T>(os, "n"));

   return os;

}

       

template<typename T>

std::ostream &operator <<(std::ostream &os, const std::vector<std::vector<T>> &v) {

   using namespace std;

 

   //NOTE: for some reason std::copy doesn't work here, so I use manual loop

   //copy(v.begin(), v.end(), ostream_iterator<std::vector<T>>(os, "n"));

 

   for(size_t i = 0 ; i < v.size(); ++i)

        os << v[i] << "n";

   return os;

}

       

std::vector<int>  v;

std::vector<std::vector<int>>  vv;

std::vector<std::vector<std::vector<int>>>  vvv;

std::vector<std::vector<std::vector<std::vector<int>>>>  vvvv;

 

std::cout << v << std::endl; //ok

std::cout << vv << std::endl; //ok

std::cout << vvv << std::endl; //ok

std::cout << vvvv << std::endl; //ok

       

template<typename T>

std::ostream &operator <<(std::ostream &os, const std::vector<T> &v) {

  for(auto const& i : v)

    os << i << "n";

  return os;

}