Is there any way to access a local variable in outer scope in C++?

Question

Just out of curiosity: if I have nested scopes, like in this sample C++ code

using namespace std;

int v = 1; // global

int main (void)
{
    int v = 2; //          


        

Answer 1

There are two types of scope resolution operators in C++ - unary scope and a class scope. There is no function scope or "any particular parent scope" resolution operators. That makes it impossible to solve your problem, as it is, in general because you cannot refer to anonymous scopes. However, you can either create an alias, rename variables, or make this a part of the class, which of course implies a code change. This is the closest I can get you without renaming in this particular case:

#include 

using namespace std;

int v = 1; // global

class Program
{
    static int v; // local

public:
    static int main ()
    {
        int v = 3; // within subscope
        cout << "subscope: " << v << endl;
        cout << "local: " << Program::v << endl; 
        cout << "global: " << ::v << endl;
    }
};

int Program::v = 2;

int main ()
{
    return Program::main ();
}

There are other ways, like making sure that variables are not optimized out and are on stack, then you can work with stack directly to get the value of the variable you want, but let's not go that way.

Hope it helps!