Const and Non-Const Operator Overloading

by

When both versions are available, the logic is pretty straightforward: const version is called for const objects, non-const version is called for non-const objects. That’s all.

In your code sample a is a non-const object, meaning that the non-const version is called in all cases. The const version is never called in your sample.

The point of having two versions is to implement “read/write” access for non-const objects and only “read” access for const objects. For const objects const version of operator [] is called, which returns a const double & reference. You can read data through that const reference, but your can’t write through it.

More Related Contents:

  1. Calling a const function rather than its non-const version
  2. Differences with const keyword in C++
  3. How to convert a std::string to const char* or char*
  4. Is it better in C++ to pass by value or pass by constant reference?
  5. Use of ‘const’ for function parameters
  6. Const before or const after?
  7. How to properly overload the
  8. Why override operator()?
  9. Overload resolution failure when streaming object via implicit conversion to string
  10. Is it better in C++ to pass by value or pass by reference-to-const?
  11. C++ Const Usage Explanation
  12. Does const-correctness give the compiler more room for optimization?
  13. Top-level const doesn’t influence a function signature
  14. Does “const” just mean read-only or something more?
  15. Why istream object can be used as a bool expression?
  16. Why does “extern const int n;” not work as expected?
  17. Why does C++ not have a const constructor?
  18. Why use a const member function?
  19. Is there actually a reason why overloaded && and || don’t short circuit?
  20. Using the less than comparison operator for strings
  21. C++ overloading array operator
  22. Overloading assignment operator in C++
  23. Can’t Overload operator
  24. How do I call the original “operator new” if I have overloaded it?
  25. constexpr vs. static const: Which one to prefer?
  26. Is it allowed to cast away const on a const-defined object as long as it is not actually modified?
  27. Returning non-const reference from a const member function
  28. How is its lifetime of a return value extended to the scope of the calling function when it is bound to a const reference in the calling function?
  29. Why we need to return reference to istream/ostream while overloading >> and
  30. using declaration in variadic template

Leave a Comment