Language: C++

#include <iostream>
#include <vector>

using namespace std;

#define rep(i,n) for(int i = 0; i < (n); i++)

int main() {
  int H, W;
  cin >> H >> W;
  vector<vector<string> > G(H);
  rep(i, H) {
    cin >> G[i];
  }
  vector<int> rows, cols;
  rep(i, H) {
    bool ok = true;
    rep(k, W) if (G[i][k] == '.') {
      ok = false;
      break;
    }
    if (ok) rows.push_back(i);
  }
  rep(k, W) {
    bool ok = true;
    rep(i, H) if (G[i][k] == '.') {
      ok = false;
      break;
    }
    if (ok) cols.push_back(i);
  }
  for (auto r : rows) {
    for (auto c : cols) cout << G[r][c];
    cout << endl;
  }
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:13:9: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'})
   13 |     cin >> G[i];
In file included from /usr/include/c++/14/iostream:42,
                 from a.cc:1:
/usr/include/c++/14/istream:170:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:24: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'bool&'
  170 |       operator>>(bool& __n)
      |                  ~~~~~~^~~
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]'
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:25: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'short int&'
  174 |       operator>>(short& __n);
      |                  ~~~~~~~^~~
/usr/include/c++/14/istream:177:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:34: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'short unsigned int&'
  177 |       operator>>(unsigned short& __n)
      |                  ~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]'
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:23: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'int&'
  181 |       operator>>(int& __n);
      |                  ~~~~~^~~
/usr/include/c++/14/istream:184:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:32: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'unsigned int&'
  184 |       operator>>(unsigned int& __n)
      |                  ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:188:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:24: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'long int&'
  188 |       operator>>(long& __n)
      |                  ~~~~~~^~~
/usr/include/c++/14/istream:192:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:33: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'long unsigned int&'
  192 |       operator>>(unsigned long& __n)
      |                  ~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:29: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'long long int&'
  199 |       operator>>(long long& __n)
      |                  ~~~~~~~~~~~^~~
/usr/include/c++/14/istream:203:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:38: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'long long unsigned int&'
  203 |       operator>>(unsigned long long& __n)
      |                  ~~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:219:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  219 |       operator>>(float& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:219:25: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'float&'
  219 |       operator>>(float& __f)
      |                  ~~~~~~~^~~
/usr/include/c++/14/istream:223:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  223 |       operator>>(double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:223:26: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'double&'
  223 |       operator>>(double& __f)
      |                  ~~~~~~~~^~~
/usr/include/c++/14/istream:227:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  227 |       operator>>(long double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:227:31: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'long double&'
  227 |       operator>>(long double& __f)
      |                  ~~~~~~~~~~~~~^~~
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:25: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::basic_string<char> > >, std::vector<std::__cxx11::basic_string<char> > >::value_type' {aka 'std::vector<std::__cxx11::basic_string<char> >'} to 'void*&'
  328 |       operator>>(void*& __p)
      |                  ~~~~~~~^~~
/usr/include/c++/14/istream:122:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__istream_type& (*)(__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]'
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:122:36: note:   no known conversion for argument 1 from '__gnu_cxx::__alloc_traits<std::allocator<std::vector<std::__cxx11::