斐波那契 非递归方法

#include <iostream>using namespace std;int Fib(int n){if(n == 0 || n == 1){return n;}int pPrev = 0;int prev = 1;int res = 0;for(int i = 2; i <= n; i++){ res = prev + pPrev; pPrev = prev; prev = res;}return res;}int main(){int sum = Fib(4);}