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.

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:

  <code class="cpp">namespace my_namespace {
    int my_var;
  }
  int main() {
    ::my_namespace::my_var = 10;
  }</code>

  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:

  <code class="cpp">class MyClass {
  public:
    static int my_class_var;
  };
  int main() {
    ::MyClass::my_class_var = 20;
  }</code>

  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:

  <code class="cpp">class MyClass {
    void my_member_function();
  };
  void MyClass::my_member_function() {
    ::cout << "Hello World!" << endl;
  }</code>

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

• Methods to access the template class:

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

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

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