scope_resolution_operator

/* The double colon in the source file (.cpp) is called the scope resolution operator, and it's used for the constructor definition:
The scope resolution operator is used to define a particular class' member functions, which have already been declared. Remember that we defined the constructor prototype in the header file.
So, basically, MyClass::MyClass() refers to the MyClass() member function - or, in this case, constructor - of the MyClass class.
It is also used for accessing global variable inside every function.
global variables having global scope.that means accessible every where inside the program.
Eg
*/
:var =10( global)

var=8; (local)

For accessing global ::var

#include "MyClass.h"

MyClass::MyClass()
{
   
}

// a function called "test", belonging to a class "demo" WARNING NO RETURN TYPE

demo::test ()
{
    
}

/*
in c++ only constructors and destructors should be written without function return type - the above is a bad teaching example