What does mean :: in c++?

Question

a little question

Answer 1

It is used to access members inside a namespace

namespace abc {
int xzy;
}

void main() {
std::cout<<abc::xyz<<std::endl;
}

Answer 2

It's a scope resolution operator
it can also be used to access global variable when you have local variable also with the same name.
Check below Url
https://www.geeksforgeeks.org/scope-resolution-operator-in-c/