Fibonacci in C++

fib.cpp

#include <iostream>
#include <functional>

int main()
{
    std::function<int(int)> fib = [&fib](int n) {return n < 2 ? 1 : fib(n-1) + fib(n-2);};
    std::cout << fib(9) << std::endl;
    return EXIT_SUCCESS;
}