Recursion calculating Legendre Polynom not working (segmentation fault) [C++]

I made a function in C++ that calculates the N-th Legendre polynomial and its derivative based on recursive formulas. It returns either zeros, bogus numbers or the "segmentation fault" error. I can't see what I did wrong. Care to help me out? Compiler is g++.

#include <iostream>#include <cmath>#include <iomanip>#include <vector>#include <functional>using namespace std;struct LegendreValues{  double function_value;  double derivative_value;};LegendreValues calculateLegendrePolynomAndDerivative(const int&, const double&);double calculateLegendrePolynom(const int&, const double&);double calculateLegendreDerivative(const int&, const double&);int main(){  int N;  LegendreValues values;  cout << "Unesite red Legendreovog polinoma: " << endl;  cin >> N;  cout << calculateLegendrePolynom(N, 0.5) << "\n" << calculateLegendreDerivative(N, 0.5) << endl;}LegendreValues calculateLegendrePolynomAndDerivative(const int& N, const double& x){  LegendreValues results;  if (N==0)  {    results.function_value = 1;    results.derivative_value = 0;  }  else if (N==1)  {    results.function_value = x;    results.derivative_value = 1;  }  else if (N>1)  {    results.function_value = (1/N) * ((2*N-1) * x * calculateLegendrePolynomAndDerivative(N-1, x).function_value - (N-1) * calculateLegendrePolynomAndDerivative(N-2, x).function_value);    results.derivative_value = N/(1-x*x) * ( calculateLegendrePolynomAndDerivative(N-1, x).function_value - x * calculateLegendrePolynomAndDerivative(N, x).function_value);  }  return results;}

The recursive formulas used:Legendre recursions

As you can see, I tried splitting the two things apart, and it still doesn't work.