How to insert an element at a specific place in a vector in C?

Question

C++ / C#

Good afternoon. There is a dynamic array implemented using vector in C.

int vector_push_back(vector_t *v, const void *item) {
    if (!v || !item) {
        return 0;
    }

    if (v->count == v->capacity) {
        if (!vector_realloc(v, v->capacity * VECTOR_SIZE_MULT)) {
            return 0;
        }
    }

    memcpy((void *)((char *)v->data + (v->count * v->item_size)), item, v->item_size);
    v->count++;

    return 1;
}

This is the function of adding a new element. How can I make it so that I can insert new elements at a specific location in an array using an index? Thanks

Answer 1

First, using memmove, you need to shift the elements from i to count-1 to positions i+1...count. Then slightly change memcopy to write the new element to position i, not count.