//main.cpp
#include <iostream>
#include <utility>

int main()
{
    auto fib = [i = 0, j = 1]() mutable {
        i = std::exchange(j, j + i);
        return i;
    };
    
    for(int i = 0; i < 10; ++i)
    {
        std::cout << fib() << " ";
    }
}

//output
1 1 2 3 5 8 13 21 34 55