Which of the following identifiers are C++ reserved words, standard, other valid , or invalid identifiers?

[bluethernet]

Okay this is a question from my homework, and I'm a bit confused, especially with Standard identifiers and Other valid identifiers. I mean what's the difference ?. Anyway, Here are my answers so far:

void - Reserved word
MAX-ENTRIES - valid Identifier
double - Reserved Word
time - valid Identifier
G - valid Identifier
Sue's - Invalid identifier
return - Reserved word
cout - Standard Identifier
xyz123 - Valid Identifier
part#2 - Invalid Identifier
"char" - Invalid Identifier
#include - Invalid Identifier ?????????????
This_is_a_long-one - Valid Identifier
_xyz - Invalid Identifier
9xyz - Invalid Identifier
main - Reserved word
mutable - Reserved word
double - Reserved word
max?out - invalid identifier



Am I correct ? Correct me if I'm wrong, please :).

[eypros]

so you should classify these "words" in which categories:
Standard identifier, valid , invalid identifier and reserved word?

Also _xyz is a valid identifier.

I am not sure I follow your classification. For example "char" is invalid identifier but it's string literal. You came up with the categories?

[bluethernet]

That's how the question is. I just edited off a bit so It could fit in the title. Here's the full thing:

Question 1: Which of the following identifiers is (a) C++ reserved words, (b) standard identifiers, (c) other valid identifiers, and (e) invalid identifiers?

And if it matters, we are operating on Visual Studio 2008.

[Alrededor]

MAX-ENTRIES - valid Identifier

Depending on the actual context, this would be interpreted as the identifier MAX minus (subtract) the identifier ENTRIES. You cannot use a hyphen in an identifier.

[Athar]

Also, time is a function in the standard library. main is not a reserved word. #include can be considered one.

[Duthomhas]

This_is_a_long-oneThis is not a valid identifier. (They are two valid identifiers separated by a 'minus' symbol.)

#include is (d) none of the above. It is a pre-processor directive, but given the options, you are correct.

BTW, I don't like the term "invalid identifier" applied here. Either it is an identifier or it is not. An identifier is only invalid when it cannot be used where it is found.

[bluethernet]

Athar, I think at the point we are in right now, its not MAX(minus)ENTRIES. Its just a dash.

Alright so I just looked at the slides and our instructor's definition of Standard identifiers are those reserved for using namespace std;

So this is pretty much my new solution. Anything wrong going on ?


void - Reserved word
MAX-ENTRIES - valid Identifier
double - Reserved Word
time - valid Identifier
G - valid Identifier
Sue's - Invalid identifier
return - Reserved word
cout - Standard Identifier
xyz123 - Valid Identifier
part#2 - Invalid Identifier
"char" - Invalid Identifier
#include - Invalid Identifier
This_is_a_long-one - Valid Identifier
_xyz - Valid Identifier
9xyz - Invalid Identifier
main - Standard Identifier
mutable - C++ Reserved word
double - C++ Reserved word
max?out - invalid identifier

I think that #include is an invalid identifier as he included the #. If it was just include, it would've been a reserved word.

I tried using time as an identifier doing int time=4; then cout<<time; and it showed 4 as an output. I assume it should be considered as a valid identifier ?

[ne555]

dash can't be part of an identifier.
You can use letters (either upper or lowercase^*), digits (but can't start with one) or underscore.

Dunno what do you mean with standard identifier.

^*keep in mind that c++ is case sensitive

[Athar]

I tried using time as an identifier doing int time=4; then cout<<time; and it showed 4 as an output. I assume it should be considered as a valid identifier ?

It is a valid identifier. Just like cout is. If you consider cout a "standard identifier", then time is too.

I think that #include is an invalid identifier as he included the #. If it was just include, it would've been a reserved word.

include is not a keyword. However, #include is a preprocessor directive.