visual studio gives undeclared identifier error

Question

my project was working fine and then when i change something in another header file i suddenly got this error:

Error C2065 'map': undeclared identifier

although i did #include <map>

part of Game.h:

#include <map>

class Game{

    Game();

}

the line which gives me the error in Game.cpp:

_results.insert(map<std::string, int>::value_type(_players[i]->getUsername(), 0));

this code line worked fine ! until some point

always use `std::` before names from the standard headers. [It makes life easier](http://stackoverflow.com/questions/1452721/why-is-using-namespace-std-in-c-considered-bad-practice) — NathanOliver, Jul 21 '16 at 16:03
The code you've pasted won't even compile (you're missing a semicolon after `}`). Please post a full example. — Sean, Jul 21 '16 at 16:03
I recommend using std::make_pair() instead of map::value_type btw. — Julian Declercq, Jul 21 '16 at 16:11
Silly question, do you have `#include ` as one of your includes? — StaticBeagle, Jul 21 '16 at 16:15

score 0 · Accepted Answer · answered Jul 21 '16 at 16:47

My guess is that at one point, you either had a class named map in the global namespace, which provided an interface similar to std::map, or more likely, you were relying on a using namespace std; directive that has since been removed (whether unintentionally or not; perhaps someone else had one in a header you were using, but removed it when they realised that was a bad idea). Either put a using-directive for std or a using-declaration for std::map in the code block containing that line, or explicitly use std::map whenever you want to use the C++ standard library map class; the latter is recommended, because it makes code clearer and cleaner.

If you were using a custom map class before, check that its header is still #included, and that it doesn't run into the same namespace issue.

#include using namespace std; all tstrings are undeclared under visual stupidity 2003, HALLLLLP. — Owl, Jun 28 '17 at 14:48

visual studio gives undeclared identifier error

1 Answers1