#include <iostream>
#include <Windows.h>
using namespace std;

//part A
float getElement(size_t n, float prev, float D)
{
    if (n <= 1)
        return prev;
    return getElement(n - 1, prev * D, D);
};

//part B
float summaryEngine(size_t n, float& summary, float prev, float D)
{
    if (n <= 1)
        return summary;
    summary += prev * D;
    return summaryEngine(n - 1, summary, prev * D, D);
};

float getSummary(size_t n, float first, float D)
{
    return summaryEngine(n, first, first, D);
};

//Main
int main()
{
    float first, D;
    size_t N;

    cout << "Enter the first element = ";
    cin >> first;
    cout << "Enter D = ";
    cin >> D;
    cout << "Enter N = ";
    cin >> N;

    // PART A
    cout << "Element number N = " << getElement(N, first, D);

    // PART B
    cout << endl << "Summary of N elements = " << getSummary(N, first, D);
    return 0;
};