Why does C use the Scope Resolution Operator ::?

Why C Employs the Scope Resolution Operator ::

In the world of C , the scope resolution operator, denoted by "::," holds a significant distinction from its counterpart, the "." operator. While other languages, such as Java, utilize a single operator for various purposes, C opts for a dedicated operator specifically tailored for resolving ambiguities between member variables and class names.

The peculiarity of C 's requirement for a separate operator stems from the language's ability to define scenarios where member variables and derived class types share the same name. Consider the following code sample:

struct foo {
  int blah;
};

struct thingy {
  int data;
};

struct bar : public foo {
  thingy foo;
};

int main() {
  bar test;
  test.foo.data = 5;
  test.foo::blah = 10;
  return 0;
}

In this example, the member variable foo in the derived class bar shares the same name as the parent class foo. To differentiate between the two, C employs the scope resolution operator, allowing the sole reference to the derived class using "::foo::blah." This ambiguity resolution mechanism becomes essential in such circumstances.

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