#include <iostream>
#include <time.h>
#include <cmath>
using namespace std;
double tiesioginis(int n);
double rec1(int n);
double rec2_start(int n);//pagalbine funkcija vartotojui, kad ivedinetu i argumentus tik 1 skaiciu
double rec2(double &Sprev, double &aprev, int i, int n);
double vs = 0;
double rez;
#define VS_ON
int main()
{
    clock_t t1, t2;
    for (int i = 1; i < 19; i++) {
        int kart = 1000000;
        t1 = clock();
        for (int k = 0; k < kart; k++) {
            vs = 0;
            rez = tiesioginis(i);
        }
        t2 = clock();
        cout << i << " " << rez << " " << ((float)(t2 - t1)) / (float)(CLOCKS_PER_SEC*kart) << " " << vs << endl;
    }
    //system("pause");
    return 0;
}
double tiesioginis(int n) {
    double a = 3. / 5.;
    double S = a;
    for (int i = 1; i <= n; i++) {
#ifdef VS_ON
        vs += 4;
#endif
        a = (1 / (double)i)*(pow((3. / 5.), (double)i));
        S += a;
    }
    return S;
}
double rec1(int n) {
    if (n < 1)
        return 3. / 5.;
#ifdef VS_ON
    vs += 5;
#endif
    return rec1(n - 1) + (1 / (double)n)*(pow((3. / 5.), (double)n));
}
double rec2_start(int n) {
    double a1 = 3. / 5.;
    double S = a1;
    return rec2(S, a1, 2, n);
}
double rec2(double &Sprev, double &aprev, int i, int n) {
    if (i > n)
        return Sprev;
    aprev = aprev * (((double)i - 3.) / (5.*(double)i));
    Sprev += aprev;
#ifdef VS_ON
    vs += 5;
#endif
    return rec2(Sprev, aprev, i + 1, n);
}