C++ error: 'unordered_map' does not name a type

Question

I am doing everything correctly as far as I can tell and I have gotten the error message:

error: \'unordered_map\' does not name a type
error: \'mymap\' does         


        

Answer 1

Compile with g++ -std=c++11 (my gcc version is gcc 4.7.2) AND

#include 
#include 

using namespace std;

//global variable
unordered_map mymap;

int main() {
  mymap.reserve(7000); // <-- try putting it here
  return 0;
}