Can't access inner class member with outer class object

Question

#include 

class Outer
{
    int o;
public:
    void setOuter(int o)
    {
        this->o=o;
    }
    class Inner
    {
    public:
        int i;
          


        

Answer 1

Inner is just a class defined at a different scope. It's no different than saying

class Inner
{
public:
    int i;
    int retOuter(Outer *obj)
    {
        return obj->o;
    }
};

and then

Inner::i =50

which obviously isn't possible because i isn't static.

Declaring an inner class doesn't automagically declare a member of that type for the outer class which you can access using that syntax.

Now, something like:

class Outer
{
    int o;
public:
    void setOuter(int o)
    {
        this->o=o;
    }
    class Inner
    {
    public:
        int i;
        int retOuter(Outer *obj)
        {
            return obj->o;
        }
    } innerMember;
    //    ^^^
    // declare a member
};

int main(int argc, char **argv) {
    Outer *obj1=new Outer;
    obj1->innerMember.i =50; //Access the inner class members by Outer class object!
}

would work.