Как обраиться к структуре в классе?

#include <iostream>
using namespace std;
 
    class cd
{
 
    private:
    char *performers;
    char *label;
    int selections;
    double playtime;
 
    public:
    struct st1
    {
        double * dpoint;
        int mass1[10];
    };
    cd();
    cd(char *s1, char *s2, double x);
    cd(const cd &obj);
    ~cd();
    cd& operator=(const cd &obj);
    friend ostream& operator<<(ostream &os, const cd &obj);
 
    void report()const;
};
 
    class classic : public cd
{
    private:
    char idenf[20];
 
    public:
    classic(char *id, char *s1, char *s2, double x);
    classic(char *id, const cd &cdobj1);
};

#include <iostream>
using namespace std;
 
    cd::cd()
{
    cout << "Default cd constructor\n";
    performers = new char;
    performers[0] = '\0';
    label = new char;
    label[0] = '\0';
    st1.dpoint = new double;
    *st1.dpoint = 0;
    st1.mass1[0] = 0;
    selections = 0;
    playtime = 0;
}
 
    cd::cd(char *s1, char *s2, double x)
{
    cout << "Cd constructor with parameters\n";
    performers = new char [strlen(s1)+1];
    strcpy(performers, s1);
    label = new char[strlen(s2)+1];
    strcpy(label, s2);
    selections = 0;
    playtime = x;
}
    cd::cd(const cd &obj)
{
    cout << "Cd copy constructor\n";
    performers = new char [strlen(obj.performers)+1];
    strcpy(performers, obj.performers);
    label = new char [strlen(obj.label)+1];
    strcpy(label, obj.label);
    selections = obj.selections;
    playtime = obj.playtime;
}
    cd& cd::operator=(const cd &obj)
{
    cout << "Cd operator =\n";
    if(this==&obj)
        return *this;
    delete performers;
    performers = new char [strlen(obj.performers)+1];
    strcpy(performers, obj.performers);
    delete label;
    label = new char [strlen(obj.label)+1];
    strcpy(label, obj.label);
    selections = obj.selections;
    playtime = obj.playtime;
    return *this;
}
    cd::~cd()
{
    cout << "Cd destructor\n";
    delete performers;
    delete label;
}
 
    ostream& operator<<(ostream &os, const cd &obj)
{
    os << "\n";
    return os;
}
    void cd::report()const
{
    cout << performers << "\n";
    cout << label << "\n";
    cout << playtime << "\n";
}
 
    void func1(const cd obj)
{
    obj.report();
}

#include <stdafx.h>
#include <iostream>
#include "incl.h"
#include "project161.cpp"
 
using namespace std;
 
    int main()
{   cd cdobj2;
    cd cdobj1("Name unknown", "Label unknown", 15.4);
    cdobj1.report();
    cdobj2 = cdobj1;
    cdobj2.report();
    func1(cdobj1);
    return 0;
}

st1::dpoint

cd::st1 s1;

cd c;
c.st.dpoint = ...;

template<class T>
class List
{
    struct Node
    {
        Node(T el):elem(el), next(0), prev(0)
        {
        }
        Node* next;
        Node* prev;
        T elem;
     };
public:
   List():head(0), tail(0)
   {
   }
private:
   Node* head;
   Node* tail;
};