Vector3D

#include <iostream>
#include "windows.h"
#include <string>
#include <new>


using namespace std;


class v3d {
public:
    double* arr;

    v3d() {
        cout << "Tworzymy... ";
        arr = new double[3];
        cout << this << " gotowe." << endl;
    }

    ~v3d() {
        cout << "Usuwamy... " << this;
        delete[] arr;
        cout << " gotowe." << endl;
    }

    v3d(const v3d& other)
    {
        arr = new double[3];
        arr[0] = other.arr[0];
        arr[1] = other.arr[1];
        arr[2] = other.arr[2];
    }



    v3d operator + (const v3d& other)
    {
        v3d temp;
        temp.arr[0] = arr[0] + other.arr[0];
        temp.arr[1] = arr[1] + other.arr[1];
        temp.arr[2] = arr[2] + other.arr[2];
        return temp;
    }
    v3d& operator += (const v3d& other)
    {
        arr[0] += other.arr[0];
        arr[1] += other.arr[1];
        arr[2] += other.arr[2];
        return *this;
    }

    v3d operator - (const v3d& other)
    {
        v3d temp;
        temp.arr[0] = arr[0] - other.arr[0];
        temp.arr[1] = arr[1] - other.arr[1];
        temp.arr[2] = arr[2] - other.arr[2];
        return temp;
    }
    v3d& operator -= (const v3d& other)
    {
        arr[0] -= other.arr[0];
        arr[1] -= other.arr[1];
        arr[2] -= other.arr[2];
        return *this;
    }

    v3d operator * (const v3d& other)
    {
        v3d temp;
        temp.arr[0] = arr[1] * other.arr[2] - arr[2] * other.arr[1];
        temp.arr[1] = arr[2] * other.arr[0] - arr[0] - other.arr[2];
        temp.arr[2] = arr[0] * other.arr[1] - arr[1] - other.arr[0];
        return temp;
    }



    v3d& operator = (const v3d& other)
    {
        if (this != &other)
        {
            arr[0] = other.arr[0];
            arr[1] = other.arr[1];
            arr[2] = other.arr[2];
        }
        return *this;
    }

    double len() {
        return pow(pow(arr[0], 2) + pow(arr[1], 2) + pow(arr[2], 2), 0.5);
    }

    string to_str() {
        return "[" + to_string(arr[0]) + ", " + to_string(arr[1]) + ", " + to_string(arr[2]) + "]";
    }
};


int main()
{
    v3d a, b, sum;

    a.arr[0] = 12;
    a.arr[1] = -56;
    a.arr[2] = 5e-3;

    b.arr[0] = 7 - 3e2;
    b.arr[1] = 24.789;
    b.arr[2] = 1;

    sum = a*b;

    cout << sum.to_str() << endl << sum.len() << endl;
    system("pause");
    return 0;
}