C中的malloc 2d数组 [英] malloc 2d arrays in C

问题描述

我有一种将信息存储在2D数组中的结构:

I have a structure to store information in a 2D array:

struct slopes {
    int size;
    int ** slope_array;
};

我为结构分配了所需的内存(数组的尺寸为s * s):

I malloc the required memory for the structure(the array has dimensions of s*s):

struct slopes * slope=malloc(sizeof(struct slopes));
slope->size=s;
slope->slope_array=malloc(sizeof(int *)*s);
int i;
for(i=0;i<s;i++) {
    slope->slope_array=malloc(sizeof(int)*s);
}

但是这些行似乎会引发细分错误:

But lines such as these seem to throw segmentation errors:

slope->slope_array[0][0]=3;

有人可以看到我在做什么吗?

Can someone see what I'm doing wrong?

推荐答案

在您的 for 循环中，您需要初始化 slope-> slope_array [i] ，而不是 slope-> slope_array :

In your for loop, you need to initialize slope->slope_array[i], not slope->slope_array:

for (i = 0; i < s; i++) {
    slope->slope_array[i] = malloc(sizeof(int)*s);
}

注意:如果您已将来自 malloc 的返回调用转换为 int * ，则编译器会警告您有关此错误的信息...

Note: if you had cast the return call from malloc to an int *, the compiler would have warned you about this error...

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