typedef struct vector_ {
      void** data;
      int size;
      int count;
} vector;

void vector_add(vector*, void*);
void vector_add(vector *v, void *e)
{
    if (v->size == 0) {
        v->size = 10;
        v->data = malloc(sizeof(void*) * v->size);
        memset(v->data, '', sizeof(void*) * v->size);
    }

if (v->size == v->count) {
    v->size *= 2;
    v->data = realloc(v->data, sizeof(void*) * v->size);
}

v->data[v->count] = e;
v->count++;
}