CppLearning/EssentialCpp/main.cpp

#include <iostream>

using namespace std;

bool Fibon_Elem(int pos, int& elem) {
	bool ret = false;
	elem = 1;
	int first = 1, second = 1;
	
	if (pos <= 0) {
		return ret;
	}

	for (int ix = 3; ix <= pos; ++ix) {
		elem = first + second;
		first = second;
		second = elem;
	}
	return true;
}

 
int main() {
	int elem = 0;
	bool ret = false;
	for (int i = 0; i < 10; ++i) {
		ret = Fibon_Elem(i, elem);
		if (!ret)
			cout << "Position " << i <<" is invalid!" << endl;
		else
			cout << "ret=" << ret << " " << elem << endl;
	}
	
}