#ifndef ARRAY2D_HPP
#define ARRAY2D_HPP

#include <iostream>
#include <stdexcept>
// 这里仅以int二维数组为例，扩展为类模板很容易
// 相比第一个版本，增加了复制构造、复制赋值、移动构造和移动赋值

class Array2D
{
    int **arr;    // 指针数组退化为二级指针
    int row, col; // 二维数组的行和列
public:
    Array2D(int _row, int _col) : row{_row}, col{_col}
    {
        // 先申请行，再申请列
        arr = new int *[row]; // 设置行 每个元素都是int *
        for (int i{0}; i < row; ++i)
            arr[i] = new int[col];
    }
    ~Array2D()
    {
        // 注意释放的次序！
        for (int i{0}; i < row; ++i)
            delete[] arr[i];
        delete[] arr;
    }
    Array2D(const Array2D &arr2d) : row{arr2d.row}, col{arr2d.col}
    {
        arr = new int *[row];
        for (int i{0}; i < row; ++i)
        {
            arr[i] = new int[col];
            for (int j{0}; j < col; ++j)
                arr[i][j] = arr2d.arr[i][j];
        }
    }
    Array2D &operator=(const Array2D &arr2d)
    {
        if (this == &arr2d)
            return *this; // 避免自赋值
        std::cout << "Copy Assign\n";
        this->~Array2D();
        row = arr2d.row;
        col = arr2d.col;
        arr = new int *[row];
        for (int i{0}; i < row; ++i)
        {
            arr[i] = new int[col];
            for (int j{0}; j < col; ++j)
                arr[i][j] = arr2d.arr[i][j];
        }
        return *this;
    }
    Array2D(Array2D &&arr2d) : row{arr2d.row}, col{arr2d.col}
    {
        std::cout << "Move Construct\n";
        arr = arr2d.arr; // 直接复制指针本身
        arr2d.col = arr2d.row = 0;
        arr2d.arr = nullptr; // 被移动的对象指针可置空
    }
    Array2D &operator=(Array2D &&arr2d)
    {
        std::cout << "Move Assign\n";
        if (this == &arr2d)
            return *this;
        this->~Array2D(); // 释放已有内存
        row = arr2d.row, col = arr2d.col;
        arr = arr2d.arr;
        arr2d.col = arr2d.row = 0;
        arr2d.arr = nullptr;
        return *this;
    }

    void print()
    {
        for (int i{0}; i < row; ++i)
        {
            for (int j{0}; j < col; ++j)
                std::cout << arr[i][j] << '\t';
            std::cout << '\n';
        }
    }
    int *operator[](int i) const // 重载[]，允许暴露内部数据
    {
        if (i < 0 || i >= row)
            throw std::out_of_range{"数组行下标越界\n"};
        return arr[i];
    }
};

#endif