将元素插入结构向量

Question

I want to initialize a struct using a function and also insert into it as seen below. I want to initialize the array dynamically I want to declare two struct vectors, one dynamically and the other statically

Answer 1

Your initialize() function is not allocating any memory for the array, and it is also not initializing the current_size to the correct value. It needs to look like this instead:

void initialize(vector &vec, int size){
    vec.current_size = 0;
    vec.array = new int[size];
    vec.max_size = size;
}

And then you need a function to free the array when you are done using it, eg:

void finalize(vector &vec){
    delete[] vec.array;
    vec.current_size = 0;
    vec.max_size = 0;
}

Also, your insert() function should be updated to avoid a buffer overflow once the array fills up to its max capacity:

void insert( vector &vec, int element){
    if (vec.current_size < vec.max_size){
        vec.array[vec.current_size] = element;
        vec.current_size++;
    }
}

If needed, this would also allow you to grow the array instead:

void insert( vector &vec, int element){
    if (vec.current_size == vec.max_size){
        int new_max = vec.max_size * 2;
        int *new_array = new int[new_max];
        for(int i = 0; i < vec.current_size; ++i){
            new_array[i] = vec.array[i];
        }
        delete[] vec.array;
        vec.array = new_array;
        vec.max_size = new_max;
    }
    vec.array[vec.current_size] = element;
    vec.current_size++;
}