【运算符重载】数组类实现

#include <iostream>
#include <cstring>
using namespace std;
class Array2
{
public:
    Array2(int m_, int n_) : m(m_), n(n_)
    {
        arr = new int *[m_];
        for (int i = 0; i < m_; ++i)
            arr[i] = new int[n_];
    }
    Array2() : m(0), n(0)
    {
        arr = NULL;
    }
    Array2 &operator=(const Array2 &a)
    {
        if (this == &a)
            return *this;
        m = a.m;
        n = a.n;
        if (arr)
        {
            for (int i = 0; i < m; ++i)
                delete[] arr[i];
            delete[] arr;
        }
        if (a.arr)
        {
            arr = new int *[m];
            for (int i = 0; i < m; ++i)
                arr[i] = new int[n];
            for (int i = 0; i < m; ++i)
                for (int j = 0; j < n; ++j)
                    arr[i][j] = a.arr[i][j];
        }
        else
            arr = NULL;
        return *this;
    }
    ~Array2()
    {
        if (arr)
        {
            for (int i = 0; i < m; ++i)
                delete[] arr[i];
            delete[] arr;
            arr = NULL;
        }
    }
    int *operator[](int m)
    {
        return arr[m];
    }
    int &operator()(int i, int j)
    {
        return arr[i][j];
    }
    int **arr;
    int m, n;
};
int main()
{
    Array2 a(3, 4);
    int i, j;
    for (i = 0; i < 3; ++i)
        for (j = 0; j < 4; j++)
            a[i][j] = i * 4 + j;
    for (i = 0; i < 3; ++i)
    {
        for (j = 0; j < 4; j++)
        {
            cout << a(i, j) << ",";
        }
        cout << endl;
    }
    cout << "next" << endl;
    Array2 b;
    b = a;
    for (i = 0; i < 3; ++i)
    {
        for (j = 0; j < 4; j++)
        {
            cout << b[i][j] << ",";
        }
        cout << endl;
    }
    return 0;
}

• 主要考察”()”和”[]”运算符的重载,同时考察了二维数组指针的动态申请和拷贝等操作
  • 关注“()”和“[]”运算符的重载
  • 注意二维数组的申请，申请第二维的时候是for(i=0; i < m; ++i)，不是for(i=0; i < n; ++i)