段错误 - 声明和init数组用C [英] Segmentation Fault - declare and init array in C

问题描述

我很新的C.在Python，Java和C＃的世界即将到来。这可能是一个愚蠢的问题，但我得到分段错误：

I am very new to C. coming from Python, Java and C# worlds. This might be a stupid question but I am getting segmentation fault:

// struct for storing matrices
typedef struct {
    int m;
    int n;   
    float* elts;
} Matrix;

在我的主要方法：

and in my main method:

 Matrix A;
    A.n = 3;
    A.m = 3;
    memcpy( A.elts, (float[]) {1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f}, 9 * sizeof(float));  // seg fault because of this memcpy.

我也试过没有˚F，同样的问题。
你能帮助，请

I also tried without the f, same issue. Can you help please

推荐答案

您需要分配为 A.elts 内存为指向。你可以用的malloc 做到这一点。你所要做的是应对你成任何地址指定的常量数组的ELT 恰好指向（这是未初始化）。

You need to allocate memory for A.elts to point to. You can do this with malloc. What you are doing is coping the constant array you specified into whatever address elts happens to point to (it is uninitialized).

您还可以指向 A.elts 来的常量数组，像这样：

You can also point A.elts to the constant array like so:

float *myFloats = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f };
A.elts = myFloats;

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