这个解除分配正确吗? [英] Is this deallocation correct?

问题描述

我分配了一个3x3 2D动态数组，如下所示:

I've a 3x3 2D dynamic array allocated as below:

int** matrix = new int* [3];
matrix[0] = new int [3*3];
for (int i = 1; i < 3; ++i)
    matrix[i] = matrix[i-1] + 3;

我应该如何分配它?这是正确的吗?

How should I deallocate it? Is this correct:

delete [] matrix;

delete [] matrix[0];

或者我也应该删除matrix[1]，[2]

推荐答案

您拥有它的方式，您应该:

The way you have it, you should :

delete [] matrix[0];
delete [] matrix;

但这是分配动态2D数组的非常常规的方式.通常，您分配一个指针数组，然后为每一行(列)分配一个实际类型的数组.

But this is a very unconventional way of allocating a dynamic 2D array. Normally you allocate an array of pointers, and then you allocate an array of your actual type for every row (column).

// allocate
int **matrix = new int*[3];
for(int i = 0; i &lt 3; ++i)
  matrix[i] = new int[3];

// deallocate
for(int i = 0; i &lt 3; ++i)
  delete [] matrix[i];

delete [] matrix;

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