Hi Neil.

11-Apr-04 15:31:00, Neil Heller wrote to Bill Birrell



 NH> That bring up an interesting point.  It is such a common thing to
 NH> compare the loop counter to a result involving the loop counter in
 NH> some sort of function

 NH> (ie:  (for n=0; n that I would consider it only natural that any optimizing compiler
 NH> would do what you did, only automatically.  Is this the case?  Or
 NH> should I be concerned with optimizing manually - not trusting the
 NH> compiler manufacturer?

The compiler doesn't understand strlen.

the C copiler understands all the keywords processd the #defines etc
but all library functions are treated as black boxes.

So. it can't know that it always returns the same value if given the same
string, and even if it did it has no easy way to tell if the for loop will
modify the string.

assuming that target and the string are unmodifieed in the body of the
loop: the above for...  is better written

 for( n=0; target[n]; n++ ) {

which is another way of saying.

 (for n=0; target[n] != '\0' ; n++) {

and possibly even better re-written to use a char* instead

 for( s=target ; *s ; s++ ) {

 -=> Bye <=-

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