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new的对象可以直接用析构函数代替delete删除吗?

 3 years ago
source link: https://www.zhihu.com/question/466944998/answer/1957874795
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new的对象可以直接用析构函数代替delete删除吗? - 知乎
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C++程序猿, 公众号：高级开发者

如果你是placement new，那是可以的。

template<class T, std::size_t N>
class static_vector
{
    // properly aligned uninitialized storage for N T's
    std::aligned_storage_t<sizeof(T), alignof(T)> data[N];
    std::size_t m_size = 0;
 
public:
    // Create an object in aligned storage
    template<typename ...Args> void emplace_back(Args&&... args) 
    {
        if( m_size >= N ) // possible error handling
            throw std::bad_alloc{};
 
        // construct value in memory of aligned storage
        // using inplace operator new
        new(&data[m_size]) T(std::forward<Args>(args)...);
        ++m_size;
    }
 
    // Access an object in aligned storage
    const T& operator[](std::size_t pos) const 
    {
        return *reinterpret_cast<const T*>(&data[pos]);
    }
 
    // Delete objects from aligned storage
    ~static_vector() 
    {
        for(std::size_t pos = 0; pos < m_size; ++pos) {
            reinterpret_cast<T*>(&data[pos])->~T();
        }
    }
};

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