Bjarne Stroustrup's c++ programming language 4th edition desk calculator example

[pyroclasticPointer]

So I've been writing the desk calculator example in chapter 10 of the book, but it won't run because the implementation of the function current(); in the token_stream class seems to be missing. Now, I really couldn't find it in the book which lead me to think that either Bjarne deliberately left it out or it's an error in the book. The current() function is declared and is called lots of times in the program, but no implementation. I searched in google and really couldn't find it. To those who have the book, is this an error?

[MiiNiPaa]

It looks like it really missing. Implementation shold be:

Lexer::Token& Lexer::Token_stream::current() 
{ 
    return ct;
};

EDIT: I have second printing. It might be fixed in 3rd one.