I am trying to understand what this declaration means. is it a function or a variable declaration? When I try to compile it in c or c++, it doesn't compile. However I found this code as part of a optimized solution to a question I was trying to solve, that is why I'm trying to figure it out.
int any = []() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
return 0;
}();
It is an immediately invoked lambda expression:
[] is an empty capture list;
() is an empty argument list;
{...} is a lambda body, that should return something that is convertible to an int, because it needs to be assigned to any.
Everything above defines a lambda.
() is a (function) call to that lambda with an empty argument list.
Lambda expressions are available since C++11, so maybe your compiler is using an outdated standard.
