c - 如何释放结构数组

Question

我有一个结构 complex 和一个结构 complex_set(一组复数)，我有“构造函数”和“析构函数”alloc_set 和 free_set。

我的问题是，在 free_set 中的 for 循环的第二次迭代中出现以下错误:

malloc: *** error for object 0x1001054f0: pointer being freed was not allocated

取消初始化 complex_set 的正确方法是什么？我想知道 complex_set 的 *points 属性是否只需要通过在第一点调用 free 来释放(然后它将释放其余的)或分别释放每个元素？还是我在初始化时已经做错了什么？

代码如下:

typedef struct complex complex;
typedef struct complex_set complex_set;

struct complex { double a; double b; };
struct complex_set {
    int num_points_in_set;
    complex *points; // an array of struct complex
};

struct complex_set *alloc_set(complex c_arr[], int size) {
    complex_set *set = (complex_set *) malloc(sizeof(complex_set));
    set->num_points_in_set = size;
    // i think i may even just use the pointer c_arr as '*points'
    // however, i want to make sure malloc was called
    set->points = (complex *) malloc(size*sizeof(complex));
    for (int i=0; i<size; i++) {
        set->points[i] = c_arr[i];
    }
    return set;
}

void free_set(complex_set *set) {
    complex *current = set->points;
    complex *next = NULL;
    int iterations = set->num_points_in_set;
    for(int i=0; i<iterations; i++) {
        next = current + 1;
        // i get the error here, in the second iteration:
        free(current);
        current = next;
    }
    free(set);
    set = NULL;
}

Answer 1

你只为 set->points 做了一个 malloc()，所以你应该只做一个 free()。

您正在尝试释放每个点。