#include <iostream>
#include "windows.h"
#include <vector>
#include <string>
#include <conio.h>
#include <functional>

using namespace std;

HANDLE hCon = GetStdHandle(STD_OUTPUT_HANDLE);
#define WIDTH 80
#define HEIGHT 30

void print(const char text[], int x, int y)
{
    COORD pos;
    pos.X = x;
    pos.Y = y;
    SetConsoleCursorPosition(hCon, pos);
    cout << text;
}

class menu
{
    vector <string> points;
    vector <function<void()>> actions;
    int point = 0;
    void show()
    {
        system("cls");
        int xMiddle = WIDTH / 2;
        int yPart = HEIGHT / (points.size() + 1);
        for (int i = 0; i < points.size(); i++)
        {
            if (i == point)
            {
                string temp = "<<" + points[i] + ">>";
                print(temp.c_str(), xMiddle - temp.length() / 2, yPart*(i+1));
            }
            else
                print(points[i].c_str(), xMiddle - points[i].length() / 2, yPart*(i+1));
        }
    }
    void up()
    {
        point = point == 0 ? points.size() - 1 : point - 1;
    }
    void down()
    {
        point = point == points.size() - 1 ? 0 : point + 1;
    }
    void enter()
    {
        actions[point]();
    }
    public:
        void add(string newP, function<void()> newA)
        {
            points.push_back(newP);
            actions.push_back(newA);
        }
        void get()
        {
            show();
            int button;
            while (true)
            {
                button = _getch();
                switch (button)
                {
                case 72:
                    up();
                    break;
                case 80:
                    down();
                    break;
                case 13:
                    enter();
                    break;
                case 27:
                    return;
                    break;
                }
                show();
            }
        }
};

void calck_sin()
{
    system("cls");
    print("sin", WIDTH / 2, HEIGHT / 2);
    cin.get();
}

void calck_cos()
{
}

void calck_simple()
{
}

int main()
{
    string resize = "mode "+ to_string(WIDTH)+ ", "+ to_string(HEIGHT);
    system(resize.c_str());
    menu first;
    first.add("sin", calck_sin);
    first.add("cos", calck_cos);
    first.add("simple function", calck_simple);
    first.get();
}