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HomeBackend DevelopmentC++What is the symbol :: in c++?

The :: symbol in C is the scope operator used to resolve name conflicts and access identifiers in other scopes, including: Accessing global variables: Access global variables by prefixing the namespace name. Access class members: Access class member variables or static member functions by prefixing the class name. Access member functions outside the class: Allows use of member functions from outside the class. Access template class methods: Access template class methods for a specific instantiation.

What is the symbol :: in c++?

The ::symbol in C

In the C programming language, :: The symbol represents the scope operator, which is used to access identifiers within nested scopes.

Role

:: Symbol is used to resolve name conflicts and access identifiers in other scopes.

Usage

  • Access global variables:

    namespace my_namespace {
      int my_var;
    }
    int main() {
      ::my_namespace::my_var = 10;
    }

    In this example, ::my_namespace ::my_var allows access to my_var variables defined in the my_namespace namespace from the main function.

  • Access class members:

    class MyClass {
    public:
      static int my_class_var;
    };
    int main() {
      ::MyClass::my_class_var = 20;
    }

    Here, ::MyClass::my_class_var allows access to the static member variable my_class_var of the MyClass class from the main function .

  • Accessing member functions outside the class:

    class MyClass {
      void my_member_function();
    };
    void MyClass::my_member_function() {
      ::cout << "Hello World!" << endl;
    }

    By using ::, you can access the member functions of a class from outside the class.

  • Methods to access the template class:

    template <typename T>
    class MyTemplate {
    public:
      static void my_method();
    };
    void MyTemplate<int>::my_method() {
      ::cout << "This is an int template!" << endl;
    }

    Using the :: notation, you can access the methods of a specific instantiation of the template class.

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