Actually, most modern compilers warn you if you do...

        while (*dest++ = *source++);

...with a message like "Possibly incorrect assignment", so I usually
include the explicit comparison.  I'm a big believer in readability, I
hate going back to some of my own old code and not being able to
figure out what I did, or why.

Martin R. Green
elimar@bigfoot.com

On Fri, 10 Oct 1997 09:33:26 +1000, Clyde Smith-Stubbs
<clyde@HTSOFT.COM> wrote:

>On Thu, Oct 09, 1997 at 03:48:51PM -0800, Andrew Warren wrote:
>> Martin R. Green <PICLIST@MITVMA.MIT.EDU> wrote:
>> > >
>> > >        while (*dest++ = *source++);
>> >
>> > Copy the thing pointed to by the source pointer to the location
>> > pointed to by the dest pointer, and increment the source and dest
>> > pointers AFTER the thing has been copied, ready for the next thing.
>>
>>     After every copy from source to destination, the "while" examines
>>     the value that was copied.  If the value isn't equal to 0,   the
>
>Just to expand further, this is really equivalent to
>
>        while((*dest++ = *source++) != 0)
>                continue;
>
>And it's actually not a bad idea to write it like that. It should generate
>exactly the same code as the original (if it doesn't, get a new compiler)
>and it makes it clear what you're doing. In Java, using the explicit !=
>test is mandatory - Java does not allow arbitrary expressions to be used as
>boolean values, to avoid errors like:
>
>        if(fred = 1)
>
>which is legal C, but almost certainly was meant to be
>
>        if(fred == 1)
>
>Then there's the hoary old trap that I still fall into occasionally:
>
>        if(fred & 0x60 == 0x20)
>
>which should have been
>
>        if((fred & 0x60) == 0x20)
>
>becuz & has a lower precedence than ==.