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

You can't execute arbitrary expressions at global scope, so you should put

mymap.reserve(7000);

inside main.

This is also true for other STL containers like map and vector.