#include <stdio.h>
#include <math.h>

enum electric_lamps{
    Incandescent_lamps,
    Compact_fluorescent_lamps,
    Halogen_lamps,
    Metal_halide_Lamps,
    Light_Emitting_Diode,
    Fluorescent_tube,
    Neon_lamps,
    High_intensity_discharge_lamps
};

typedef struct rectangle rectangle;

struct rectangle{
    double points_[3][2];

    double (*get_perimeter)(rectangle*);
    double (*get_square)(rectangle*);
};

double sqr(double d1){
    return d1 * d1;
}

double get_perimeter(rectangle* rect){
    return 2 * sqrt(sqr(rect->points_[0][0] - rect->points_[1][0]) +
                sqr(rect->points_[0][1] - rect->points_[1][1])) +
            2 * sqrt(sqr(rect->points_[0][0] - rect->points_[2][0]) +
                sqr(rect->points_[0][1] - rect->points_[2][1]));
}

double get_square(rectangle* rect){
    return  sqrt(sqr(rect->points_[0][0] - rect->points_[1][0]) +
                    sqr(rect->points_[0][1] - rect->points_[1][1])) *
            sqrt(sqr(rect->points_[0][0] - rect->points_[2][0]) +
             sqr(rect->points_[0][1] - rect->points_[2][1]));
}

struct MP3{
    unsigned Play : 1;
    unsigned Pause : 1;
    unsigned Record : 1;
};

typedef union check check;

union check{
    char input;
    struct MP3 a;
};

int main(){
    enum electric_lamps el = Halogen_lamps;
    printf("%d\n", el);

    rectangle rect = {.points_ = {{1, 0}, {0, 1}, {1, 1}},
        .get_perimeter = get_perimeter,
        .get_square = get_square
    };

    double p = rect.get_perimeter(&rect);
    double s = rect.get_square(&rect);
    printf("perimeter is %lf\n", p);
    printf("square is %lf\n", s);

    int hex;
    printf("enter MP3 options in hex:\n");
    scanf("%x", &hex);

    check ch;
    ch.input = hex;
    printf("Play: %d, Pause: %d, Record: %d\n",
           ch.a.Play, ch.a.Pause, ch.a.Record);

    return 0;
}