Help for a Beginner?

[duojet2ez]

Hello,

I am trying to make a text based game and had the idea to use a json file to store all of the text for each page. And then I can conveniently turn the text into a json object and in my main.cpp output the text from the json file.

Because I am new (barely figured out how to get this library installed) I am having a hell of a time understanding the documentation. Is my stated objective possible?

The only thing I have figured out how to do is store text in a json file:

{
"text": "goes here"

}

and then in my main.cpp file I call that text by opening and reading into the file:

 std::ifstream inFile("pagetest.json");  
json j; 
inFile >> j; 
std::string s = j.dump(); 
std::cout << s << std::endl; 

However, this does not behave as I'd expect. It outputs everything including the quotations and the {} which is what I don't want. I would need just a string outputted.

Basically I am very confused.... Any help would be greatly appreciated.

[nlohmann]

If you only need the value at key "text", do this:

std::cout << j["text"] << std::endl;

If you do not want the quotes (i.e., a serialize JSON value of type string), but a std::string, do this:

std::string s = j["text"];
std::cout << s << std::endl;

[duojet2ez]

Fantastic that worked!!! So simple! Thank you for answering. I am slowly understanding the power of json.

[nonetrix]

This worked but I tried to do something like this
std::string title = reddit_result[0]["data"]["children"][0]["data"]["title"] + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];

But that does this:

./main.cpp: In function ‘int main()’:
./main.cpp:52:82: error: no match for ‘operator+’ (operand types are ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} and ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’})
   52 | title = reddit_result[0]["data"]["children"][0]["data"]["title"] + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/stl_algobase.h:67,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/algorithm:61,
                 from ././json.hpp:37,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/stl_iterator.h:1239:5: note: candidate: ‘template<class _Iterator, class _Container> __gnu_cxx::__normal_iterator<_Iterator, _Container> __gnu_cxx::operator+(typename __gnu_cxx::__normal_iterator<_Iterator, _Container>::difference_type, const __gnu_cxx::__normal_iterator<_Iterator, _Container>&)’
 1239 |     operator+(typename __normal_iterator<_Iterator, _Container>::difference_type
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/stl_iterator.h:1239:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const __gnu_cxx::__normal_iterator<_Iterator, _Container>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/stl_algobase.h:67,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/algorithm:61,
                 from ././json.hpp:37,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/stl_iterator.h:565:5: note: candidate: ‘template<class _Iterator> constexpr std::reverse_iterator<_Iterator> std::operator+(typename std::reverse_iterator<_Iterator>::difference_type, const std::reverse_iterator<_Iterator>&)’
  565 |     operator+(typename reverse_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/stl_iterator.h:565:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::reverse_iterator<_Iterator>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/stl_algobase.h:67,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/algorithm:61,
                 from ././json.hpp:37,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/stl_iterator.h:1646:5: note: candidate: ‘template<class _Iterator> constexpr std::move_iterator<_IteratorL> std::operator+(typename std::move_iterator<_IteratorL>::difference_type, const std::move_iterator<_IteratorL>&)’
 1646 |     operator+(typename move_iterator<_Iterator>::difference_type __n,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/stl_iterator.h:1646:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::move_iterator<_IteratorL>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:55,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6081:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&, const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&)’
 6081 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6081:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:56,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.tcc:1169:5  note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&)’
 1169 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.tcc:1169:5  note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   mismatched types ‘const _CharT*’ and ‘nlohmann::basic_json<>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:56,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.tcc:1189:5  note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(_CharT, const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&)’
 1189 |     operator+(_CharT __lhs, const basic_string<_CharT, _Traits, _Alloc>& __rhs)
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.tcc:1189:5  note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:55,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6118:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)’
 6118 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6118:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:55,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6134:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&, _CharT)’
 6134 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs, _CharT __rhs)
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6134:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:55,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6146:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&)’
 6146 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6146:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘std::__cxx11::basic_string<_CharT, _Traits, _Allocator>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:55,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6152:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&, std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&&)’
 6152 |     operator+(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6152:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:55,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6158:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&&)’
 6158 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6158:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘std::__cxx11::basic_string<_CharT, _Traits, _Allocator>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:55,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6180:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(const _CharT*, std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&&)’
 6180 |     operator+(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6180:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   mismatched types ‘const _CharT*’ and ‘nlohmann::basic_json<>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:55,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6186:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(_CharT, std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&&)’
 6186 |     operator+(_CharT __lhs,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6186:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘std::__cxx11::basic_string<_CharT, _Traits, _Allocator>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:55,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6192:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, const _CharT*)’
 6192 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6192:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘std::__cxx11::basic_string<_CharT, _Traits, _Allocator>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/string:55,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/locale_classes.h:40,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/ios_base.h:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/streambuf:41,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/streambuf_iterator.h:35,
                 from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/iterator:66,
                 from ././json.hpp:42,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6198:5: note: candidate: ‘template<class _CharT, class _Traits, class _Alloc> std::__cxx11::basic_string<_CharT, _Traits, _Allocator> std::operator+(std::__cxx11::basic_string<_CharT, _Traits, _Allocator>&&, _CharT)’
 6198 |     operator+(basic_string<_CharT, _Traits, _Alloc>&& __lhs,
      |     ^~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/basic_string.h:6198:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘std::__cxx11::basic_string<_CharT, _Traits, _Allocator>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/valarray:603,
                 from ././json.hpp:67,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/valarray_after.h:405:5: note: candidate: ‘template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__plus, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__plus, typename _Dom1::value_type>::result_type> std::operator+(const std::_Expr<_Dom1, typename _Dom1::value_type>&, const std::_Expr<_Dom2, typename _Dom2::value_type>&)’
  405 |     _DEFINE_EXPR_BINARY_OPERATOR(+, struct std::__plus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/valarray_after.h:405:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/valarray:603,
                 from ././json.hpp:67,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/valarray_after.h:405:5: note: candidate: ‘template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__plus, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename std::__fun<std::__plus, typename _Dom1::value_type>::result_type> std::operator+(const std::_Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)’
  405 |     _DEFINE_EXPR_BINARY_OPERATOR(+, struct std::__plus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/valarray_after.h:405:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/valarray:603,
                 from ././json.hpp:67,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/valarray_after.h:405:5: note: candidate: ‘template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__plus, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__plus, typename _Dom1::value_type>::result_type> std::operator+(const typename _Dom::value_type&, const std::_Expr<_Dom1, typename _Dom1::value_type>&)’
  405 |     _DEFINE_EXPR_BINARY_OPERATOR(+, struct std::__plus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/valarray_after.h:405:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/valarray:603,
                 from ././json.hpp:67,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/valarray_after.h:405:5: note: candidate: ‘template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__plus, std::_Expr, std::_ValArray, _Dom, typename _Dom::value_type>, typename std::__fun<std::__plus, typename _Dom1::value_type>::result_type> std::operator+(const std::_Expr<_Dom1, typename _Dom1::value_type>&, const std::valarray<typename _Dom::value_type>&)’
  405 |     _DEFINE_EXPR_BINARY_OPERATOR(+, struct std::__plus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/valarray_after.h:405:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from /usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/valarray:603,
                 from ././json.hpp:67,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/valarray_after.h:405:5: note: candidate: ‘template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__plus, std::_ValArray, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__plus, typename _Dom1::value_type>::result_type> std::operator+(const std::valarray<typename _Dom::value_type>&, const std::_Expr<_Dom1, typename _Dom1::value_type>&)’
  405 |     _DEFINE_EXPR_BINARY_OPERATOR(+, struct std::__plus)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/bits/valarray_after.h:405:5: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::_Expr<_Dom1, typename _Dom1::value_type>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from ././json.hpp:67,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/valarray:1185:1: note: candidate: ‘template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__plus, std::_ValArray, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__plus, _Tp>::result_type> std::operator+(const std::valarray<_Tp>&, const std::valarray<_Tp>&)’
 1185 | _DEFINE_BINARY_OPERATOR(+, __plus)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/valarray:1185:1: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::valarray<_Tp>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from ././json.hpp:67,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/valarray:1185:1: note: candidate: ‘template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__plus, std::_ValArray, std::_Constant, _Tp, _Tp>, typename std::__fun<std::__plus, _Tp>::result_type> std::operator+(const std::valarray<_Tp>&, const typename std::valarray<_Tp>::value_type&)’
 1185 | _DEFINE_BINARY_OPERATOR(+, __plus)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/valarray:1185:1: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::valarray<_Tp>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

In file included from ././json.hpp:67,
                 from ./main.cpp:1:
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/valarray:1185:1: note: candidate: ‘template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__plus, std::_Constant, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__plus, _Tp>::result_type> std::operator+(const typename std::valarray<_Tp>::value_type&, const std::valarray<_Tp>&)’
 1185 | _DEFINE_BINARY_OPERATOR(+, __plus)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/include/g++-v11/valarray:1185:1: note:   template argument deduction/substitution failed:
./main.cpp:52:156: note:   ‘nlohmann::basic_json<>::value_type’ {aka ‘nlohmann::basic_json<>’} is not derived from ‘const std::valarray<_Tp>’
   52 | + reddit_result[0]["data"]["children"][0]["data"]["url_overridden_by_dest"];
      |                                                                           ^

Also is there a better way to do this? allocating memory just to print something without quotation marks doesn't seem ideal

[gregmarr]

@nonetrix reddit_result[0]["data"]["children"][0]["data"]["title"] is of type nlohmann::json, you need to get the actual string from it to combine it with another string. You can do that without copying using the get_ref() function. I think it would be written as get_ref<const std::string&>() but I haven't compiled and tested to be sure.
https://nlohmann.github.io/json/api/basic_json/get_ref/