我怎么可以连接在C中的两个阵列？ [英] How can I concatenate two arrays in C?

问题描述

我如何连接两个阵列以获得含有原数组的元素单一阵列？

How do I concatenate two arrays to get a single array containing the elements of both original arrays?

推荐答案

在C数组简单地是一个连续的内存区，一个指向其开始*。因此，合并它们包括：

Arrays in C simply are a contiguous area of memory, with a pointer to their start*. So merging them involves:

1. 找到了数组a和b的长度，（你可能需要知道的元素数和的sizeof 每个元素）
2. 分配（的malloc ）的新数组C，它是A + B的大小。
3. 复制（的memcpy ）从A内存为C，
4. 从b将存储到C + A（参见图1）的长度。
5. 您可能还需要取消分配（免费）A和B的记忆。

1. Find the length of the arrays A and B, (you will probably need to know the number of elements and the sizeof each element)
2. Allocating (malloc) a new array C that is the size of A + B.
3. Copy (memcpy) the memory from A to C,
4. Copy the memory from B to C + the length of A (see 1).
5. You might want also to de-allocate (free) the memory of A and B.

请注意，这是一个昂贵的操作，但是这是基本理论。如果您正在使用一个库，它提供了一些抽象，你可能会更好。如果A和B是比较复杂的，然后一个简单的数组（比如排序数组），您需要做聪明的复制，然后步骤3和4（参见：<一href="http://stackoverflow.com/questions/1700182/how-do-i-merge-two-arrays-having-different-values-into-one-array">how我该合并具有不同的值到一个数组）两个数组。

Note that this is an expensive operation, but this is the basic theory. If you are using a library that provides some abstraction, you might be better off. If A and B are more complicated then a simple array (e.g. sorted arrays), you will need to do smarter copying then steps 3 and 4 (see: how do i merge two arrays having different values into one array).

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• 虽然这个问题的目的，指针的解释就足够了，严格来说（和平息下面的评论者）：C的的的数组的概念，即可以在没有语法使用的指针。实现明智的，但是，一个C阵列和一个连续的内存区，指针都足够接近，他们可以，而且经常是，交替使用。

• Although for the purpose of this question, the pointer explanation will suffice, strictly speaking (and for pacifying the commenter below): C has the concept of an array, that can be used without the syntax of pointers. Implementation wise, however, a C array and a contiguous area of memory, with a pointer are close enough they can be, and often are, used interchangeably.

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