C新手求教各位大佬这题咋做，真心感谢

Question

Answer 1

#include<iostream>
using namespace std;

int fib(int n)
{
    if (n <= 0) { return 0; }
    else if (1 == n) { return 1; }
    else if (2 == n) { return 2; }
    else { return fib(n - 1) + fib(n - 2); }
}

int main()
{
    int n = 0;
    cout << "Input data: ";
    if ((cin >> n) && (n > 0)) 
    {
        double sum = 0;
        for (int i = 1; i <= n; ++i)
        {
            cout << fib(i + 1) << "/" << fib(i);

            if (i < n) { cout << " + "; }

            if (fib(i) <= 0) { continue; }

            sum += (double)fib(i + 1) / (double)fib(i);
        }

        cout << " = " << sum << endl;
    }
    else { cout << "Input Error!" << endl; }

    return 0;
}