C++11的default和delete关键字

class CString
{
    char* _str;

public:
    //构造函数
    CString(const char* pstr) : _str(nullptr)
    {
        UpdateString(pstr);
    }

    //析构函数
    ~CString()
    {
        if (_str)
            free(_str);
    }

public:
    void UpdateString(const char* pstr) throw()
    {
        if (pstr == nullptr)
            return;

        if (_str)
            free(_str);

        _str = (char*)malloc(strlen(pstr) + 1);
        strcpy(_str,pstr);
    }

public:
    char* GetStr() const throw()
    {
        return _str;
    }
};

auto str = std::make_unique<CString>("123");
printf(str->GetStr());

auto str = std::make_unique<CString>(); //失败，因为没有一个无参构造函数

class CString
{
    char* _str = nullptr;
    
public:
    CString() = default;

public:
    //构造函数
    CString(const char* pstr) : _str(nullptr)
    {
        UpdateString(pstr);
    }

    //析构函数
    ~CString()
    {
        if (_str)
            free(_str);
    }

public:
    void UpdateString(const char* pstr) throw()
    {
        if (pstr == nullptr)
            return;

        if (_str)
            free(_str);

        _str = (char*)malloc(strlen(pstr) + 1);
        strcpy(_str,pstr);
    }

public:
    char* GetStr() const throw()
    {
        return _str;
    }
};

auto str_def = std::make_unique<CString>();
str_def->UpdateString(“123”);
printf(str_def->GetStr() == nullptr ? "None":str_def->GetStr());

template<typename T>
class CStackMemoryAlloctor
{
    mutable T* _ptr;

public:
    explicit CStackMemoryAlloctor(size_t size) throw() : _ptr(nullptr)
    {
        _ptr = (T*)malloc(size);
    }

    ~CStackMemoryAlloctor()
    {
        if (_ptr)
            free(_ptr);
    }

public:
    operator T*() const throw()
    {
        T* tmp = _ptr;
        _ptr = nullptr;
        return tmp;
    }

public:
    T* GetPtr() const throw()
    {
        return _ptr;
    }
};

CStackMemoryAlloctor<wchar_t> str(128);
wchar_t* pstr = str.GetPtr();
wcscpy(pstr,L"123\n");
wprintf(pstr);

auto p = std::make_unique<CStackMemoryAlloctor<wchar_t>>(128);

private:
    void* operator new(std::size_t)
    {
        return nullptr;
    }

public:
    void* operator new(std::size_t) = delete;

C++11的default和delete关键字

原文：http://blog.csdn.net/a1875566250/article/details/40406883