In C++, the scope resolution operator (::) is used to specify the scope of a name, such as a class name or a namespace name. It is used to indicate that the name being referred to is not in the current scope, but in a different scope.

For example, the scope resolution operator can be used to access a member of a class from outside the class:

class MyClass
{
public:
int x;
};

int main()
{
MyClass obj;
obj.x = 10; // Accesses the member x of the class MyClass
return 0;
}

The scope resolution operator can also be used to access a global variable or a function that has been declared in a namespace:

namespace MyNamespace
{
int x;
void foo() { }
}

int main()
{
MyNamespace::x = 10; // Accesses the global variable x in the namespace MyNamespace
MyNamespace::foo(); // Calls the function foo in the namespace MyNamespace
return 0;
}

Overall, the scope resolution operator is an important concept in C++ programming, and it is used to specify the scope of a name and to access members of a class, variables, and functions from outside their scope.