// LETIINF3.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "cmath"
#include "iostream"

double a, b, r;

double f_line(double x)
{
    double x1 = 0;
    double y1 = b;
    double x2 = 2 * a;
    double y2 = -b;
    return  ((y1 - y2)*x + (x1*y2 - x2*y1)) / (x1 - x2);
}
double s_line(double x)
{
    double x1 = 2 * a;
    double y1 = -b;
    double x2 = 4 * a;
    double y2 = b;
    return  ((y1 - y2)*x + (x1*y2 - x2*y1)) / (x1 - x2);
}
double get_y(double x)
{
    if (x <= 0)
    {
        return get_y(4 * a - fmod(x, 4 * a));
    }
    else {
        if (x <= 2 * a)
        {
            return  f_line(x);
        }
        else
        {
            if (x <= 4 * a)
            {
                return s_line(x);
            }
            else
            {
                return get_y(fmod(x, 4 * a));
            }
        }
    }
}

void main()
{
    double x, y;
    std::cout << "a - 1\n";
    //std::cin >> a;
    a = 1;
    std::cout << "b - 1\n";
    //std::cin >> b;
    b = 1;
    std::cout << "x - ";
    std::cin >> x;

    y = get_y(x);
    y = y == -0 ? fabs(y) : y;
    std::cout << y << "\n";
    system("PAUSE");
}