What does the scope resolution operator '::' do in c++? Why do we have to use it while declaring the function outside the class?

Question

'::' scope resolution operator in c++

Answer 1

The :: (scope resolution) operator is used to get hidden names due to variable scopes so that you can still use them. The scope resolution operator can be used as both unary and binary.
from: tutorialspoint.com
In other words, with this operator you are pointing to the source of that function.