FixedBuffer Class Template

#include <iostream>
#include <array>
using namespace std;

template<typename T, size_t N>
class FixedBuffer {
public:
    void push(T v) {
        if (i != N) a[i++] = v;
    }
    size_t size() const {
        return i;
    }
    T operator[](size_t ii) const {

        if (ii >= i) throw std::out_of_range("FixedBuffer out of range"); 
        return a[ii];
    }
private:
    array<T, N> a;
    typename array<T, N>::size_type i{0};
};

int main() {
   int n;
   cin >> n;
   FixedBuffer<int, 10> buf;  // max 10 elements
   for (int i = 0; i < n; i++) {
       int v;
       cin >> v;
       buf.push(v);
   }
   cout << "Buffer size: " << buf.size() << "\n";
   for (size_t i = 0; i < buf.size(); i++) {
       cout << buf[i] << " ";
   }
   cout << "\n";
   return 0;
}