#include <iostream> #include <cassert> using namespace std; int fibon_elem(int pos) { assert(pos > 0); int elem = 1; int n1 = 1,n2 = 1; int iCnt; for (iCnt = 3; iCnt <= pos;++iCnt) { elem = n1 + n2; n1 = n2; n2 = elem; } return elem; } int main(void) { fibon_elem(10); fibon_elem(-1); return 0; }