Why do I need to explicitly write the 'auto' keyword?

Question

I am moving towards C++11 from C++98 and have become familiar with the auto keyword. I was wondering why we need to explicitly declare auto if the

Answer 1

auto is a keyword which you can use in places where you normally need to specify a type.

  int x = some_function();

Can be made more generic by making the int type automatically deduced:

  auto x = some_function();

So it's a conservative extension to the language; it fits into the existing syntax. Without it x = some_function() becomes an assignment statement, no longer a declaration.