Difference between decltype and typeof?

Question

Two question regarding decltype and typeof:

• Is there any difference between the decltype and typeof operato

Answer 1

Well, typeof is a non-standard GNU C extension that you can use in GNU C++ because GCC allows you to use features from other languages in another (not always though), so they really shouldn't be compared.

Of course other non-standard extensions may exist for other compilers, but GCC is definitely the most widely documented implementation.

To answer the question: it can't be obsolete if it was never a feature.

If you want to compare the merits of either method in C++ then there is semantically no difference unless you're dealing with references. You should use decltype because it is portable and standards conforming.