C++: Is there a Value used to designate the end-of-an-array for non-char arrays?

C++: Is there a Value used to designate the end-of-an-array for non-char arrays?

[Robert Miesen]

Hi.

I am curious if there is any sort of value used to designate the end of 
an array for arrays that are not of type char. I checked the book, "The 
C Programming Language", the book, "C++: The Complete Reference, 4th 
ed.", and briefly checked and found no information on the value used to 
designate the end of a non-character array.

Does such an end-of-array value exist for arrays that are not character 
arrays? Thank you for your responses in advance

Re: C++: Is there a Value used to designate the end-of-an-array for non-char arrays?

[John Love-Jensen]

Hi Robert,

> I am curious if there is any sort of value used to designate the end of
> an array for arrays that are not of type char.

Nothing in particular is used by convention.

You can create your own convention, if you so choose and it works for the
numbers you are working with.  For example, if I had an array of floats that
were between -1.0f and +1.0f, I could choose some arbitrary number, say
2.0f, to represent end-of-array.

Alternatively, I could associate an array length size_t and not have an
explicit end-of-array value.

HTH,
--Eljay

Re: C++: Is there a Value used to designate the end-of-an-array for non-char arrays?

[Perry Smith]

In general, no.

For some specific instances, there is a value but that value is put  
there by the C code (or C++ code) and not the "language" or the  
compiler.  For example, the main program is called as:  int main(int  
argc, char *argv[])  The argv array is an array of pointers to  
strings.  The last entry in the array is a null pointer.  But, as I  
said, that is set up by other code before main is called.

So, if you are writing just the receiving part of such an interface,  
check with the side that is creating the array to see if they are  
doing something similar.  Or if you are creating both sides of the  
interface, then you can design and implement whatever you desire.   
Often, with an array of structures, a particular field in the  
structure is given a special value that should never otherwise occur.

HTH,
Perry


On Jan 23, 2006, at 2:08 AM, Robert Miesen wrote:

> Hi.
>
> I am curious if there is any sort of value used to designate the  
> end of an array for arrays that are not of type char. I checked the  
> book, "The C Programming Language", the book, "C++: The Complete  
> Reference, 4th ed.", and briefly checked and found no information  
> on the value used to designate the end of a non-character array.
>
> Does such an end-of-array value exist for arrays that are not  
> character arrays? Thank you for your responses in advance
>

Re: C++: Is there a Value used to designate the end-of-an-array for non-char arrays?

[dch]

Hi Robert,

Unless you're dealing with legacy code, then with C++ std::vector or or 
std::list are the way to go.  These container classes come with end() 
methods which allow you to detect when you've reached the end of the 
container.  Even if you are dealing with legacy code, it is possible to 
pass vectors as arrays in most cases, althougth this would probably 
require more code changes than you want.

HTH,
David.

Robert Miesen wrote:

> Hi.
>
> I am curious if there is any sort of value used to designate the end 
> of an array for arrays that are not of type char. I checked the book, 
> "The C Programming Language", the book, "C++: The Complete Reference, 
> 4th ed.", and briefly checked and found no information on the value 
> used to designate the end of a non-character array.
>
> Does such an end-of-array value exist for arrays that are not 
> character arrays? Thank you for your responses in advance
>
>
>