我如何在C动态多维数组工作？ [英] How do I work with dynamic multi-dimensional arrays in C?

问题描述

有人不知道如何用C使用动态分配的多维数组？这可能吗？

Does someone know how I can use dynamically allocated multi-dimensional arrays using C? Is that possible?

推荐答案

通过动态分配，使用malloc：

With dynamic allocation, using malloc:

int** x;

x = malloc(dimension1_max * sizeof(int*));
for (int i = 0; i < dimension1_max; i++) {
  x[i] = malloc(dimension2_max * sizeof(int));
}

[...]

for (int i = 0; i < dimension1_max; i++) {
  free(x[i]);
}
free(x);

此分配大小 dimension1_max * dimension2_max 的二维数组。因此，举例来说，如果你想要一个640 * 480阵列（图像的FE像素），使用 dimension1_max = 640， dimension2_max = 480。然后，您可以使用<访问数组code> X [D1] [D2] ，其中 D 1 = 0 ..639， D 2 = 0..479。

This allocates an 2D array of size dimension1_max * dimension2_max. So, for example, if you want a 640*480 array (f.e. pixels of an image), use dimension1_max = 640, dimension2_max = 480. You can then access the array using x[d1][d2] where d1 = 0..639, d2 = 0..479.

但在搜索SO或谷歌也透露出其他的可能性，例如<一个href=\"http://stackoverflow.com/questions/365782/how-do-i-best-handle-dynamic-multi-dimensional-arrays-in-c-c\">in这太问题

But a search on SO or Google also reveals other possibilities, for example in this SO question

请注意，在那种情况可能会与该承担这个职能的问题，如果你的磁盘阵列不会分配一个连续的内存区（640 * 480字节）。因此，要获得数组满足条件，与此代替上述的malloc块：

Note that your array won't allocate a contiguous region of memory (640*480 bytes) in that case which could give problems with functions that assume this. So to get the array satisfy the condition, replace the malloc block above with this:

int** x;
int* temp;

x = malloc(dimension1_max * sizeof(int*));
temp = malloc(dimension1_max * dimension2_max * sizeof(int));
for (int i = 0; i < dimension1_max; i++) {
  x[i] = temp + (i * dimension2_max);
}

[...]

free(temp);
free(x);

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