如何自定义std::deque的分配器

在C++中，std::deque是一个双端队列容器，它使用分配器来管理其内存

1. 包含必要的头文件。

#include
#include 
#include // 为了使用 std::allocator

2. 创建自定义分配器类。

template<typename T>
class MyAllocator : public std::allocator {
public:
    using value_type = T;
    using pointer = T*;
    using const_pointer = const T*;
    using reference = T&;
    using const_reference = const T&;
    using size_type = size_t;
    using difference_type = ptrdiff_t;

    template<typename U>
    struct rebind {
        typedef MyAllocator other;
    };

    MyAllocator() noexcept {}

    MyAllocator(const MyAllocator& other) noexcept {}

    template<typename U>
    MyAllocator(const MyAllocator& other) noexcept {}

    ~MyAllocator() noexcept {}

    pointer allocate(size_type n, const void* hint = nullptr) {
        // 在这里实现自定义内存分配逻辑
        pointer result = std::allocator::allocate(n, hint);
        std::cout << "Allocated " << n * sizeof(T) << " bytes."<< std>;
        return result;
    }

    void deallocate(pointer p, size_type n) {
        // 在这里实现自定义内存释放逻辑
        std::allocator::deallocate(p, n);
        std::cout << "Deallocated " << n * sizeof(T) << " bytes."<< std>;
    }
};

int main() {
    std::deque<int, MyAllocator<int>> my_deque;

    // 向 deque 添加元素，观察自定义分配器的输出
    for (int i = 0; i < 10; ++i) {
        my_deque.push_back(i);
    }

    return 0;
}