c - 释放与列表关联的任何动态分配的内存并返回 NULL？

Question

typedef struct ArrayList
{
    // We will store an array of strings (i.e., an array of char arrays)
    char **array;

    // Size of list (i.e., number of elements that have been added to the array)
    int size;

    // Length of the array (i.e., the array's current maximum capacity)
    int capacity;

} ArrayList;

我有这个函数，它使用上面的结构为字符串数组动态分配内存:

ArrayList *createArrayList(int length){


ArrayList *n = malloc(sizeof(ArrayList));


int initial = 0, i;
n->size = initial;


if (length > DEFAULT_INIT_LEN)
{

n->array = malloc(length * sizeof(char*));
n->capacity = length;

if (n->array == NULL)
    panic("ERROR: out of memory in Mylist!\n");

for (i = 0; i< n->capacity; i++)
{
    n->array[i] = NULL;
}

}
else
{
n->array = malloc(DEFAULT_INIT_LEN * sizeof(char*));
n->capacity = DEFAULT_INIT_LEN;

if (n->array == NULL)
    panic("ERROR: out of memory in Mylist!\n");

for (i = 0; i< n->capacity; i++)
{
    n->array[i] = NULL;
}

}

printf("-> Created new ArrayList of size %d\n", n->capacity);


return n;

}

我的问题是每次我尝试在 main 中调用此函数时我的程序都会崩溃:

ArrayList *destroyArrayList(ArrayList *list)
{


    free(list);


    return NULL;

}

如何正确实现 destroyArrayList 函数来释放 createArrayList 函数分配的任何内存而不会使程序崩溃？

Answer 1

尝试以下操作

static ArrayList *n = malloc(sizeof(ArrayList));

而不是

ArrayList *n = malloc(sizeof(ArrayList));