The :: (scope resolution) operator is used to qualify hidden names so that you can still use them. You can use the unary scope operator if a namespace scope or global scope name is hidden by an explicit declaration of the same name in a block or class. For example:
int count = 0;
int main(void) {
int count = 0;
::count = 1; // set global count to 1
count = 2; // set local count to 2
return 0;
}
The declaration of count declared in the main function hides the integer named count declared in global namespace scope. The statement ::count = 1 accesses the variable named count declared in global namespace scope.
You can also use the class scope operator to qualify class names or class member names. If a class member name is hidden, you can use it by qualifying it with its class name and the class scope operator.
In the following example, the declaration of the variable X hides the class type X, but you can still use the static class member count by qualifying it with the class type X and the scope resolution operator.
#include <iostream>
using namespace std;
class X
{
public:
static int count;
};
int X::count = 10; // define static data member
int main ()
{
int X = 0; // hides class type X
cout << X::count << endl; // use static member of class X
}
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