Подскажите литературу по классам

#include <iostream>
#include <cmath>
using namespace std;
 
class Vector
{
    private:
        double x,y;
    public:
        Vector();
        ~Vector() {};
        Vector(double _x, double _y);
        void print() const; //вывод вектора
        void reset(); //устанавливает координаты вектора на (0,0);
        Vector operator+(const Vector &v) const; //суммирует два вектора
        Vector operator-(const Vector &v) const; //разность двух векторов
        Vector operator*(const Vector &v) const; //произведение двух векторов
        Vector operator*(const double n) const; //произведение вектора на N
        friend Vector operator*(double n, const Vector &v) {return v * n;};
        double dist(); //длина вектора
        friend ostream& operator<<(ostream &os, const Vector &v);
        friend istream& operator>>(istream &is, Vector &v);
};
 
int main()
{
    Vector A(2,3);
    Vector B(3,5);
    Vector C;
    C = A + B;
    cout << A << " + " << B << " = " << C << endl;
    C = A - B;
    cout << A << " - " << B << " = " << C << endl;
    C = A * B;
    cout << A << " * " << B << " = " << C << endl;
    C = A * 5;
    cout << A << " * 5 = " << C << endl;
    C = 6 * B;
    cout << "6 * " << B << " = " << C << endl;
    cout << "Вектор A -> ";
    cin >> A;
    cout << "Вектор B -> ";
    cin >> B;
    C = A + B;
    cout << A << " + " << B << " = " << C << endl;
    C = A - B;
    cout << A << " - " << B << " = " << C << endl;
    C = A * B;
    cout << A << " * " << B << " = " << C << endl;
    C = A * 5;
    cout << A << " * 5 = " << C << endl;
    C = 6 * B;
    cout << "6 * " << B << " = " << C << endl;
    return 0;
}
 
Vector::Vector()
{
    x = 0;
    y = 0;
}
 
Vector::Vector(double _x, double _y)
{
    x = _x;
    y = _y;
}
 
void Vector::reset()
{
    x = 0;
    y = 0;
}
 
void Vector::print() const
{
    cout << "(" << x << "; " << y << ")" << endl;
}
 
Vector Vector::operator+(const Vector &v) const
{
    Vector k;
    k.x = x + v.x;
    k.y = y + v.y;
    return k;
}
 
Vector Vector::operator-(const Vector &v) const
{
    Vector k;
    k.x = x - v.x;
    k.y = y - v.y;
    return k;
}
 
Vector Vector::operator*(const Vector &v) const
{
    Vector k;
    k.x = x * v.x;
    k.y = y * v.y;
    return k;
}
 
Vector Vector::operator*(const double n) const
{
    Vector k;
    k.x = x * n;
    k.y = y * n;
    return k;
}
 
double Vector::dist()
{
    return sqrt(x * x + y * y);
}
 
ostream& operator<<(ostream &os, const Vector &v)
{
    os << "(" << v.x << "; " << v.y << ")";
    return os;
}