Practice. Task 16

// vector.hpp
#ifndef _VECTOR_H_
#define _VECTOR_H_

class vector
{
private:
    double x;
    double y;

public:
    vector(double x, double y);
    friend bool operator== (vector &vector1, vector &vector2);
};

#endif

// vector.cpp
#include "vector.hpp"
#include <cmath>

vector::vector(double x, double y) {
    this->x = x;
    this->y = y;
}

bool operator== (vector &vector1, vector &vector2) {
    // модуль вектора равен квадртному корню из суммы квадратов координат вектора.
    double vector1_module = sqrt(pow(vector1.x, 2) + pow(vector1.y, 2));
    double vector2_module = sqrt(pow(vector2.x, 2) + pow(vector2.y, 2));
    return vector1_module == vector2_module;
}

// main.cpp
#include <iostream>
#include "vector.hpp"

int main(int argc, char const *argv[])
{
    vector vector1(10, 25);
    vector vector2(40, 5);
    vector vector3(25, 10);

    bool comparison1 = (vector1 == vector2);
    bool comparison2 = (vector1 == vector3);
    bool comparison3 = (vector2 == vector3);

    std::cout << std::boolalpha << comparison1 << std::endl;
    std::cout << std::boolalpha << comparison2 << std::endl;
    std::cout << std::boolalpha << comparison3 << std::endl;

    return 0;
}