again the problem: the destructor is called twice

Hi all,

I posted my question two days ago, and tried to solve this problem.
but until now I didn't solve that. and I cut my codes so maybe this
time it is more readable.

/////////////////////////////////////////////////////
#ifndef MYCLASS_H_
#define MYCLASS_H_

#include <string>
#include <list>
//#include "name.h"

using namespace std;
class myclass
{
protected:
    list<string> namelist;
// map<int,vector<name> >names;
public:

    myclass();
    myclass(const myclass &my);
    ~myclass();
// myclass& operator=(const myclass &it);
    void AddName(const string &name);
    void GetMyclass();
};

#endif

///////////////////////////////////////////////
myclass.cpp
#include "myclass.h"
#include <algorithm>
#include <iostream>

myclass::myclass()
{

}

myclass::myclass(const myclass &my)
{

    namelist=my.namelist;
}

myclass::~myclass()
{

    namelist.erase(namelist.begin(),namelist.end());
}

void myclass::AddName(const string &name)
{
    list<string>::iterator ii;
    ii=find(namelist.begin(),namelist.end(),name);

    if(ii==namelist.end())
        namelist.push_back(name);
}

void myclass::GetMyclass()
{
    list<string>::iterator ii;
    for(ii=namelist.begin();ii!=namelist.end();ii++)
        cout<<*ii<<endl;
}

/////////////////////////////////////////////////
test.h
#ifndef TEST_H_
#define TEST_H_

#include <string>
#include <map>
#include "myclass.h"

using namespace std;

class test
{
protected:
    map<string,myclass*> tests;

public:
    test();
    test(const test& mytest);
    test& operator=(const test& ts);
    ~test();
    void AddMyclass(const string &name,const myclass &my);
    void GetTest();

};

#endif

////////////////////////////////////////////////////
test.cpp

#include "test.h"

#include <utility>
#include <iostream>

test::test()
{
}
test::test(const test& mytest)
{
    tests=mytest.tests;
}

test& test::operator =(const test &ts)
{
    if(this!=&ts)
    {
        map<string,myclass*>::iterator ii;
        for(ii=tests.begin();ii!=tests.end();++ii)
            delete(ii->second);
        tests.clear();

        tests=ts.tests;
    }
    return *this;
}

test::~test()
{
    map<string,myclass*>::iterator ii;
    for(ii=tests.begin();ii!=tests.end();++ii)
        delete(ii->second);
    tests.clear();
}
void test::AddMyclass(const string &name,const myclass &my)
{
    map<string,myclass*>::iterator ii;
    myclass* newmyclass=NULL;

    ii=tests.find(name);
    if(ii==tests.end())
    {
        newmyclass=new myclass(my);
        tests[name]=newmyclass;
    }
}

void test::GetTest()
{
    map<string,myclass*>::iterator ii;
    for(ii=tests.begin();ii!=tests.end();ii++)
    {
        cout<<"the name is:"<<ii->first<<endl;
        ii->second->GetMyclass();
    }
}

////////////////////////////////////////////////////////////////////
call.h

#ifndef CALL_H_
#define CALL_H_

#include "test.h"

class call
{
public:
    inline void SetTest(const test& ts){testagain=ts;}

protected:
    test testagain;
};
#endif

///////////////////////////////////////////////////////////////////
main
#include "myclass.h"
#include "test.h"
#include "call.h"

int main()
{
    test tt;
    myclass my;
    string ss[3]={"a","b","c"};
    call ca;

    for(int i=0;i<3;i++)
        my.AddName(ss[i]);

    my.GetMyclass();

    tt.AddMyclass("my class",my);

    tt.GetTest();

    ca.SetTest(tt);
    return 0;
}

The problem is at the line ca.SetTest(tt). Could somebody tell me how
to solve it? Thanks.