C++求斐波那契数列的第n项

#include <iostream>using namespace std;int fib(int n);int main(){    int a;    while(cin>>a)    {        cout<<"the result: "<<fib(a)<<endl;    }    return 0;}int fib(int n){    if(n==1||n==2)        return 1;    else        return fib(n-1)+fib(n-2);}