插入到 C 中的动态字符串数组

Question

I'm trying to implement a dynamic array of strings. However I encountered a slight problem. I don't allocate the memory properly, but I have no idea what am doing wrong.

My structure for the dynamic array looks like:

typedef struct Array {
    char **ids;
    int size;
} dynamicArray;

I initialize it with:

void initArray(dynamicArray *array) {
    array = malloc(sizeof(dynamicArray));
    array->ids = NULL;
    array->size = 0;
}

Deallocate by:

void freeArray(dynamicArray *array) {
    if (array->size != 0) {
        for (int i = 0; i < array->size; i++) {
            free(array->ids[i]);
        }
        array->size = 0;
        array->ids = NULL;
    }
}

But now the real problem for me is inserting:

void insertArray(dynamicArray *array, char *name) {
    if (array == NULL) {
        return;
    }
    int length = strlen(name) + 1;
    array = realloc(array, (??));
    strcpy(array->ids[array->size++], name);
}

The program fails on the reallocation with: Exception has occurred. . I'm really not sure, what am I doing wrong. I know I should be also allocating the array of string, but have no idea how to put it in there. Could you guys please send me any hints??

Answer 1

The pointer that you need to reallocate is array->ids , not array . When you insert into the array you increase its size. Then the new element points to a copy of the name string.

void insertArray(dynamicArray *array, char *name) {
    if (array == NULL) {
        return;
    }
    int length = strlen(name) + 1;
    char *copy = malloc(length);
    if (copy == NULL) { // malloc failed
        return;
    }
    strcpy(copy, name);
    char **new_ids = realloc(array->ids, (array->size+1) * sizeof(char *));
    if (new_ids == NULL) { // realloc failed
        return;
    }
    array->ids = new_ids;
    array->ids[array->size++] = copy;
}