Fibonacci numbers with custom generator for C++20

_demo_generator.cpp

//Source code C++ MasterClass (Algorithms with C++ MasterClass) by Fabio Galuppo
//C++ MasterClass - https://www.linkedin.com/company/cppmasterclass - https://cppmasterclass.com.br/
//Fabio Galuppo - http://member.acm.org/~fabiogaluppo - [email protected]
//March 2025

//g++ -O3 -std=c++20 _demo_generator.cpp -o a.exe
//cl /Fo.\obj\ /EHsc /O2 /std:c++20 _demo_generator.cpp /link /out:a.exe

#include <iomanip>
#include <iostream>

#include "Generator.hpp"

//https://oeis.org/A000045
Generator<unsigned long long> fibonacci_numbers(unsigned short n)
{
    unsigned long long a = 0, b = 1;
    co_yield a;
    while (n-- > 0)
    {
        co_yield b;
        b += a;
        a = b - a; 
    }
}

int main()
{
    for (unsigned short n = 0; n <= 16; ++n)
    {
        std::cout << "Fib(" << std::setw(2) << n << "): ";
        auto gen = fibonacci_numbers(n);
        while (auto opt = gen.next())
            std::cout << *opt << ' ';
        std::cout << '\n';
    }
    return 0;
}