如何在C ++中创建动态数组数组 [英] How to create Array of Dynamic Arrays in C++

问题描述

我试图学习C ++并尝试为一个简单的哈希表写一个代码，如下面的结构：

I am trying to learn C++ and trying to write a code for a simple hash table like following structure:

array[0][0] array[0][1] array[0][2]
key 1        value 1      value 2

array[1][0] array[1][1] 
key 2        value 3     

array[2][0] array[2][1] array[2][2]
key 3        value 4      value 5

表示动态数组数组。现在，我不明白如何定义数组这样？

means Array of Dynamic Arrays. Now, I can't understand how to define the array like that ?

任何帮助将是感激。

推荐答案

如果真的需要创建一个动态数组动态数组，你必须使用 new 两个数组的关键字。例如：

If you really did need to create a dynamic array of dynamic arrays you would have to do it using the new keyword for both arrays. For example:

// an array of int pointers... each points to the start of an array
int** arrays = new int*[10]; 
arrays[0] = new int[99]; // populate the first element of the array of arrays
arrays[1] = new int[47]; // arrays don't have to be the same size.

当然，我强烈建议不要这样做。您必须记住在数组和数组的每个成员上使用 delete [] 本身。

Of course I highly recommend NOT doing this. You have to then remember to use delete[] on each member of arrays and on arrays itself.

真的你应该使用内置的 std :: vector 这个。这是为什么它在那里（我投票的其他答案！）

Really you should use the built in std::vector type for this. It is why it is there (I voted for the other answers!).

只是作为一个注释，这不是连续的内存。如果你希望成员数组的大小相同，你可以在中为循环分配它们的内存。

Just as a note, this is not contiguous memory either. Also if you do want the member arrays to be the same size you could allocate their memory in a for loop.

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