C++ 'string' does not name a type in header

Question

Eugh, 2 problems in one day. I am having one of those bad days you hear so much about. I have been organizing my small project to make it less cluttered. It's at the start of the development so there isn't much going on. I have this header below

#pragma once
#include <string>

class Game_Map
{
    private:
        int map_width;
        int map_height;
        string map_data [50][50]
    public:
        Game_Map(int default_width = 20,int default_height = 20)
        ~Game_Map()
};

Now as far as I can see, there shouldn't be any problems. I avoided using the "using" and I kept the programming up til now at the basic to prevent external interference. But am I 100% of the time getting "map.h:9:9: error: 'string' does not name a type"

I am certain I have missed something. Can anyone see where I have gone wrong?

`#pragma once` is non-portable. Use standard include guards instead. — Deduplicator, Apr 11 '14 at 17:04
`#ifndef GUARD_Game_Map\n#define GUARD_Game_Map\n/*Your code*/\n#endif` — Deduplicator, Apr 11 '14 at 17:18
Interesting. Do you have a tutorial/article on this attribute? I'd like to look into it — Jeremy Beare, Apr 11 '14 at 17:20
Just search for "include guards" on the web. Well, most modern compilers implement it. This post [Is #pragma once a safe include guard?](http://stackoverflow.com/questions/787533/is-pragma-once-a-safe-include-guard) discusses it more. — Deduplicator, Apr 11 '14 at 17:22

Nemanja Trifunovic · Answer 1 · 2014-04-11T17:12:37.093

9

Change

string map_data [50][50]

to

std::string map_data [50][50];

That's necessary because string belongs to the std namespace.

Don't use "using" declaration or directive in a header file.

edited Apr 11 '14 at 17:12

answered Apr 11 '14 at 16:28

Nemanja Trifunovic

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score 1 · Answer 2 · answered Apr 11 '14 at 16:27

1

Use either a fully qualified name (preferable) as

std::string map_data [50][50];

or use using declaration

using std::string;
string map_data [50][50];

or using directive

using namespace std;
string map_data [50][50]'

answered Apr 11 '14 at 16:27

Vlad from Moscow

301,070
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@Massa Could you point where I said that using should be included in a header?! – Vlad from Moscow Apr 12 '14 at 00:11
It's in the title of the original question, on the top of the page... `C++ 'string' does not name a type in header` – Massa Apr 12 '14 at 01:17

score 0 · Answer 3 · answered Apr 11 '14 at 17:01

You seem to miss some semicolons at the end of some lines here:

class Game_Map
{
...
    string map_data [50][50]  // Missing ;
public:
    Game_Map(int default_width = 20,int default_height = 20)  // Missing ;
    ~Game_Map() // Missing ;
};

Moreover, when you #include <string>, the "complete name" to identify the STL string class is std::string (since the STL string class is located under the std:: namespace).

So, just use std::string instead of string in this line:

std::string map_data[50][50];

Note that in header files you shouldn't use "using directives" (e.g. using namespace std;), to avoid to "pollute" the global namespace of clients that #include your header file. Just specify the STL class names with their std:: prefix in header files.

C++ 'string' does not name a type in header

3 Answers3