Question

With

#include <iostream>
using namespace std;

        int a = 1;

int main()
{
        int a = 2;

        if(true)
        {
                int a = 3;
                cout << a 
                     << " " << ::a // Can I access a = 2 here?
                     << " " << ::a << endl;
        }
        cout << a << " " << ::a << endl;
}

having the output

3 1 1
2 1

Is there a way to access the ‘a’ equal to 2 inside the if statement where there is the ‘a’ equal to 3, with the output

3 2 1
2 1

Note: I know this should not be done (and the code should not get to the point where I need to ask). This question is more “can it be done”.

Answer 1

No you can’t, a (2) is hidden.

Ref: 3.3.7/1

A name can be hidden by an explicit
declaration of that same name in a
nested declarative region or derived
class (10.2).

Ref: 3.4.3/1

The name of a class or namespace
member can be referred to after the ::
scope resolution operator (5.1)
applied to a nested-name-specifier
that nominates its class or namespace.
During the lookup for a name preceding
the :: scope resolution operator,
object, function, and enumerator names
are ignored. If the name found is not
a class-name (clause 9) or
namespace-name (7.3.1), the program is
ill-formed.