Fibonacci numbers using queue

#include <bits/stdc++.h>
using namespace std;

queue<unsigned long long> q;

void fibo_using_queue(int n){
    q.push(0);
    q.push(1);
    for (int i = 0; i < n; i++){
        unsigned long long a = q.front();q.pop();
        unsigned long long b = q.front();q.pop();
        q.push(b);
        q.push(a + b);
        cout<<a<<endl;
    }
}

int main(){
    fibo_using_queue(86);//print first 86 Fibonacci numbers
}