Implementation of static constructor in c++ doesn't work - c++

Question

http://ideone.com/1ohrsO
The push_back called inside the constructor of static_constructor, is not reflected. Why?
#include <iostream>
#include <vector>
#include<memory>
#include<string>
using namespace std;
class has_static_constructor
{
public:
friend class static_constructor;
static vector<int> v;
class static_constructor
{
public:
vector<int> * upt; //&v;
static_constructor()
{
cout<<"inside static_constructor";
upt = &has_static_constructor::v;
has_static_constructor::v.push_back(1);
has_static_constructor::v.push_back(20);
}
} ;
static std::unique_ptr<has_static_constructor::static_constructor> upt ;
};
unique_ptr<has_static_constructor::static_constructor> has_static_constructor::upt(new has_static_constructor::static_constructor());
vector< int > has_static_constructor::v(2,100);
int main() {
// your code goes here
for (std::vector<int>::const_iterator i = has_static_constructor::v.begin(); i != has_static_constructor::v.end(); ++i)
{ std::cout << *i << ' ';
cout<<"\n I was here\n";
}
return 0;
}
Output:
inside static_constructor100
I was here
100
I was here

Answer 1

static_constructor() is called before has_static_constructor::v initialization.
Move
unique_ptr<has_static_constructor::static_constructor> has_static_constructor::upt(new has_static_constructor::static_constructor());
after
vector< int > has_static_constructor::v(2,100);
to have expected behaviour.
But better avoid those global entirely.

Answer 2

You might want to have a look at this way of ordering the code. It removes all initialisation-order dependencies, and in my view neatly separates the public interface from the internal implementation of the static data.
#include <iostream>
#include <vector>
class has_static_constructor
{
// note - all private
struct static_data {
static_data()
: _v(2, 100)
{
_v.push_back(1);
_v.push_back(20);
}
std::vector<int> _v;
};
static static_data& statics() {
static static_data sd;
return sd;
}
// public interface
public:
static std::vector<int>& v() { return statics()._v; }
};
auto main() -> int
{
for (const auto& i : has_static_constructor::v())
{
std::cout << i << std::endl;
}
return 0;
}
expected output:
100
100
1
20