分段错误 - 在 C 中声明和初始化数组 [英] Segmentation Fault - declare and init array in C

问题描述

我对 C 非常陌生.来自 Python、Java 和 C# 世界.这可能是一个愚蠢的问题，但我遇到了分段错误:

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;

在我的主要方法中:

 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.可以帮忙吗

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

推荐答案

你需要为 A.elts 分配内存来指向.您可以使用 malloc 来做到这一点.您正在做的是将您指定的常量数组处理到 elts 碰巧指向的任何地址(它未初始化).

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).

您也可以将 A.elts 指向常量数组，如下所示:

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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