For kicks... Problem with this snippet?

returns 1 if both are identical ...

It will leave the loop when the strings become different or when reach the end of str1 (then, the strings are equal, or else it would already been out of the loop because the short-circuited "and" operator)

then, we have 2 options:
1) *str1 is not null .... then, the strings are different....  (because it left the loop failing in condition *str1 == *str2)
2) *str1 is null .... then, if *str2 isn't null (str1 is an empty string and str2 not, maybe str1 == #0 and str2 == "a", for example), the strings are different, else, both are identical (they got  compared every byte before it got out of the loop with *str1 == 0.

Am I wrong?

If str1 == NULL or str2 == NULL --> Bad
if len(str2) < len(str1) -> Bad - what are you peeking at beyond the end of the string? Undefined. Also might get wrong result

"if len(str2) < len(str1) -> Bad - what are you peeking at beyond the end of the string? Undefined. Also might get wrong result"
I (respectully) disagree. Will get out of the loop because (*str1 != 0) and (*str2 == 0), so (*str1 != *str2)  when we get in the end of str2 (or else, str1 == 0 mean len(str1) == len(str2)

The NULL things is right, if any of these strings is NULL, the answer is undefined (the same with strcmp, I guess, cannot compare NULL strings). My assumption was for not-null char * : ))

You could use:

while ((*str1 == *str2) && (*str1) && (*str2))  

Sorry I didn't go through the comments above. Don't know if its already been suggested.... anyway, what is the error that you got initially?

Knightmad - I agree with myself, too. Doh. Realised, about to say sorry - notice you'd beaten me to it.... Ooops

One other comment - If you have to ask whether the function works (because it's a little 'clever' and trying to be quick) then probably don't write it like that.

Something more explicit that tests both str1 and str2 etc (e.g. mayankeagle?) might be clearer. Unless you have proved otherwise, the compiler might do just as good a job (or better!) at producing final code for you..... Don't optimise unless you know you really need to!

A side-note (I'm sorry if I'm wrong)
This question seems to be a kind of "expertise test", with Axter as target
Take a look at this thread: http://www.experts-exchange.com/Programming/Programming_Languages/Cplusplus/Q_20716036.html#9200948
Just a thought ...

If i am not mistaken, NULL is C++ means (void *). Thus it can't be used in comparing the character as such , it can just be used for comparing pointers. Thus the last statement :
 return ((*str1 == NULL)  && (*str2 == NULL));

should work.

Do let me know if  i am wrong.
thanks
-manas

If i am not mistaken, NULL is C++ means (void *). Thus it can't be used in comparing the character as such , it can just be used for comparing pointers. Thus the last statement :
 return ((*str1 == NULL)  && (*str2 == NULL));

shouldn't work.

Do let me know if  i am wrong.
thanks
-manas

please ignore my first posting.  i made a typo. Consider the second answer.
thanks
-manas

I didn't look at the code itself, but certainly the arguments should be "const char*"

why return an int and not a bool ?

with an int return one might "expect" that it like
strcmp() - returns -1,0,1

Because this was from a book C/C++, illustrating the types of char ptr manipulation that might occur behind the scenes in a function like strcmp().  Axter made a scene of pointing out that this book was "not recommended" by whoever, but the reviewer used this as an example of why the book was bad... and insignificant snippet showing how to iterate through 2 strings simultaneously... Here's what the reviewer had to say about it...

"Here is another example: 'Tip 173 Determining Whether Two Strings are the Same' provides you with a function to compare two strings character by character. See how many errors you can spot...  On second thoughts why bother? Either compare the addresses if you want to answer the question as phrased, or use strcmp() if you want to see if they match. Any author who can provide you with a function that includes blatant undefined behaviour when there is a perfectly good library function does not deserve to be taken seriously"

The author didn't even point out the errors he mentioned, which BTW don't exist.  I wanted Axter to justify making a show of, and even LINKING TO, this review, which is clearly biased and uninformed.  And the book does, in fact, introduce the actual strcmp() function a couple of pages later.  Heaven forbid a new programmer actually understand how to manipulate the string himself before using the prewritten one for him!  Let's not teach kids in calculus how to do calculus either... hell, they all have TI-82s that'll do it for them, right?

I'm just wondering why Axter spent the time it would have taken to go through every single persons book recommendations looking for negative reviews, how ever fraudulant they may be, to post on that thread.