#include <iostream>
#define eps 1e-3
int F(int n)
{
    int f, f1(1), f2(1), m(0);
    while(m < n - 1)
    {
        f = f1 + f2;
        f1 = f2;
        f2 = f;
        ++m;
    }
    return f1;
}
void Fib(double a, double b)
{
    std::cout<<"\n\n\n\tМетод Фибоначчи:\n";
    double x1, x2, _x, xf1, xf2;
    int k(0);
    int N(0);
    double fn1(1), fn2(1), fn, f = (b - a) / eps;
    while(fn1 < f)
    {
        fn = fn1 + fn2;
        fn1 = fn2;
        fn2 = fn;
        ++N;
    }
    x1 = a + (double)F(N - 2) / F(N) * (b - a) - (N&1 ? -1 : 1) * eps / F(N);
    x2 = a + (double)F(N - 1) / F(N) * (b - a) + (N&1 ? -1 : 1) * eps / F(N);
    xf1 = Fun(x1);
    xf2 = Fun(x2);
  P:
    ++k;
    if(xf1 >= xf2)
    {
        a = x1;
        x1 = x2;
        xf1 = xf2;
        x2 = a + (double)F(N - k - 1) / F(N - k) * (b - a) + ((N - k)&1 ? -1 : 1) * eps / F(N - k);
        xf2 = Fun(x2); 
    }
    else
    {
        b = x2;
        x2 = x1;
        xf2 = xf1;
        x1 = a + (double)F(N - k - 2) / F(N - k) * (b - a) - ((N - k)&1 ? -1 : 1) * eps / F(N - k);
        xf1 = Fun(x1);
    }
    if(fabs(b - a) <= eps)
    {
        _x = (a + b) / 2;
        std::cout<<"Результат:\nx = "<<_x<<"\t\tF(x) = "<<Fun(_x)<<
            "\nКоличество итераций: "<<k;
    }
    else
        goto P;
}