vector_2d.cpp

#include "vector_2d.hpp"
#include <cmath>


void rotate_vectors(
    Vector2D* vector_array,
    const size_t vector_array_size,
    const double angle_in_radians
)
{
    double i, j;

    for(
        unsigned int idx = 0;
        idx < vector_array_size;
        idx++
    )
    {
        i = vector_array[idx].i;
        j = vector_array[idx].j;

        vector_array[idx].i = i * cos(angle_in_radians) -
                                j * sin(angle_in_radians);

         vector_array[idx].j = j * cos(angle_in_radians) +
                                i * sin(angle_in_radians);


    }
}