#include <vector>
    #include <string>
    #include <cctype>
    class A{
    private:
    int id, type;
    std::vector<double> fields;
    public:
    A(int ax, int bx, std::vector<double> f){
    a = ax; b = bx; fields = f;
    }
    int get_id () {return id;}
    int get_type () {return type;}
    std::vector<double> get_fields() {return fields;}
    }

    class B{
    private:
    int no_points, btype;
    double* meanz, *valuez;
    std::vector<A> as;
    public:
    B(int i, A* a, int x, int y){
    no_points = 1;
    btype = i;
    meanz = new double[x];
    valuez = new double[x];
    for(int xD = 0; xD < y; xD++){
        meanz[xD] = 0;
        valuez[xD] = 0;
    }
    if(a != NULL) as.push_back(a);
    }
    void add_A(A a, int no_fields){
    no_points++;
    for(int i = 0; i < no_fields; i++){
        valuez[i] += a.get_fields().at(i);
        meanz[i] = valuez[i] / no_points;
    }
    as.push_back(a);
    }
    bool remove_A(A a, int no_fields){
    int loc = -1;
    int search = a.get_id();
    for(int Dx = 0; Dx < no_points; Dx++){
        if(points.at(i).get_id() == search)
            loc = i;
    if(loc == -1) return false;
    no_points--;
    for(int heh = 0; heh < no_fields; heh++){
        valuez[i] -= a.get_fields().at(i);
        meanz[i] = valuez[i] / no_points;
    }
    points.erase(points.begin(), loc);
    }

    class C{
    public:
    B** bs;
    int* categories;
    std::string* typez;
    C(int no_inst){
    B = new B*[no_inst];
    categories = new int[no_inst];
    typez = new std::string[no_inst];
    for(int x = 0; x < no_inst; x++)
        categories[x] = 0;
    }
    }

[[noreturn]] static void _Xlength()
    {   // report a length_error
    _Xlength_error("vector<T> too long");
    }