When I need to implement a recursive lambda, usually I do it like this:
auto factorial = [](auto& self, int n) -> int {
return n == 0 ? 1 : n * self(self, n - 1);
};
and call it with factorial(factorial, n). However, I've seen people declaring the parameter self with type auto&& instead of auto&. What's the difference?
As @appleapple said,
no real difference in your case
That is correct. If you want to know a bit more, perhaps this will interest you: C++ auto& vs auto
What's the difference?
The lvalue reference to non-const of your example cannot bind to rvalues.
and call it with factorial(factorial, n)
If you don't ever intend pass an rvalue, then the difference is of no practical consequence.
