6.16. Unary Scope Resolution Operator
It’s possible to declare local and global variables of the same name. C++ provides the unary scope resolution operator (::) to access a global variable when a local variable of the same name is in scope. The unary scope resolution operator cannot be used to access a local variable of the same name in an outer block. A global variable can be accessed directly without the unary scope resolution operator if the name of the global variable is not the same as that of a local variable in scope.
Figure 6.21 shows the unary scope resolution operator with local and global variables of the same name (lines 6 and 10). To emphasize that the local and global versions of variable
number are distinct, the program declares ...