把Singleton作为类的成员变量

#include <iostream>

template<typename T>
class SingletonTemplate {
public:
    SingletonTemplate() {
        std::cout << "In SingletonTemplate Construct" << std::endl ;
    }

public:
    static T& Instance() {
        if(m_pInstance == NULL) {
            m_pInstance = new T ;
        }
        return *m_pInstance ;
    }

private:
    SingletonTemplate<T>* operator = (const SingletonTemplate<T>*) {}

private:
    static T* m_pInstance ;
} ;

template<typename T>
T* SingletonTemplate<T>::m_pInstance = NULL ;

class CB {
public:
    CB() {
        std::cout << "In CB Construct" << std::endl ;
    }

    ~CB() {
        std::cout << "In CB DeConstruct" << std::endl ;
    }

    void PrintFun() {
        std::cout << "value of m_i:" << m_i << std::endl ;
    }

    void SetI(int value) {
        m_i = value ;
    }

    int GetI() {
        return m_i ;
    }

private:
    int m_i ;
} ;

class CA {
public:
    SingletonTemplate<CB> m_CBInstance ;
} ;

class CC {
public:
    SingletonTemplate<CB> m_CBInstance ;
} ;

template<typename T, size_t size>
class TT {
public:
    TT() {
        std::cout << "In TT Construct, size:" << size << std::endl ;
    }
} ;

class CTestCC {
public:
    SingletonTemplate<TT<char, 1024> > m_ccInst ;
} ;

class CTestCC2 {
public:
    SingletonTemplate<TT<char, 1024> > m_ccInst_char_1024 ;
    SingletonTemplate<TT<char, 128> > m_ccInst_char_128 ;
    SingletonTemplate<TT<int, 128> > m_ccInst_int_128 ;
} ;

int main(int argc, char** argv) {
    CA* p_ca = new CA() ;
    CB* ptr = &p_ca->m_CBInstance.Instance() ;
    ptr->SetI(10) ;
    CC* p_cc = new CC() ;
    p_cc->m_CBInstance.Instance() ;
    std::cout << "Print By p_ca, i:" << p_ca->m_CBInstance.Instance().GetI() << std::endl ;
    std::cout << "Print By p_cc, i:" << p_cc->m_CBInstance.Instance().GetI() << std::endl ;

    delete p_ca ;
    p_ca = NULL ;
    delete p_cc ;
    p_cc = NULL ;

    
    std::cout << "Print By ptr, i:" << ptr->GetI() << std::endl ;
    

    CTestCC* p_testcc = new CTestCC() ;
    TT<char, 1024>* p_tt = &p_testcc->m_ccInst.Instance() ;
 
    CTestCC2* p_testcc2 = new CTestCC2() ;
    TT<char, 1024>* p_char_1024 = &p_testcc2->m_ccInst_char_1024.Instance() ;
    TT<char, 128>* p_char_128 = &p_testcc2->m_ccInst_char_128.Instance() ;
    TT<int, 128>* p_int_128 = &p_testcc2->m_ccInst_int_128.Instance() ;

    return 0 ;
}
/*
In SingletonTemplate Construct
In CB Construct
In SingletonTemplate Construct
Print By p_ca, i:10
Print By p_cc, i:10
Print By ptr, i:10

In SingletonTemplate Construct
In TT Construct, size:1024
In SingletonTemplate Construct
In SingletonTemplate Construct
In SingletonTemplate Construct
In TT Construct, size:128
In TT Construct, size:128
*/