D - Array comparisons bug - arraytest.d
- Mike Wynn <Mike_member pathlink.com> Jun 02 2002
- "Walter" <walter digitalmars.com> Jun 02 2002
- Russ Lewis <spamhole-2001-07-16 deming-os.org> Jun 02 2002
- "Alix Pexton" <Alix seven-point-star.co.uk> Jun 02 2002
- "anderson" <anderson firestar.com.au> Jun 02 2002
- "Walter" <walter digitalmars.com> Jun 02 2002
- "Pavel Minayev" <evilone omen.ru> Jun 03 2002
- "Walter" <walter digitalmars.com> Jun 03 2002
- mike.wynn l8night.co.uk Jun 03 2002
- "Walter" <walter digitalmars.com> Jun 03 2002
- "Roberto Mariottini" <rmariottini lycosmail.com> Jun 03 2002
Is this a known bug ?
Attached is small test prog that shows the problem.
char[] a = <whatever>;
char[] b = <whatever-else>;
if ( a == b )
{
// this code will be run as if the line above was
// if (a.length == b.length && a[0] == b[0])
// so this implies "pos" == "pzz" !!
}
Jun 02 2002
"Mike Wynn" <Mike_member pathlink.com> wrote in message news:add42g$4pa$1 digitaldaemon.com...Is this a known bug ? Attached is small test prog that shows the problem. char[] a = <whatever>; char[] b = <whatever-else>; if ( a == b ) { // this code will be run as if the line above was // if (a.length == b.length && a[0] == b[0]) // so this implies "pos" == "pzz" !! }
That's intended behavior. To get the behaviour you're looking for, use === (that's 3 =).
Jun 02 2002
Walter wrote:"Mike Wynn" <Mike_member pathlink.com> wrote in message news:add42g$4pa$1 digitaldaemon.com...Is this a known bug ? Attached is small test prog that shows the problem. char[] a = <whatever>; char[] b = <whatever-else>; if ( a == b ) { // this code will be run as if the line above was // if (a.length == b.length && a[0] == b[0]) // so this implies "pos" == "pzz" !! }
That's intended behavior. To get the behaviour you're looking for, use === (that's 3 =).
???????? I thought that == was to compare the references! Since "pos" and "pzz" must be in different points in memory, they cannot have the same internal pointer, and thus the test should fail, right? -- The Villagers are Online! http://villagersonline.com .[ (the fox.(quick,brown)) jumped.over(the dog.lazy) ] .[ (a version.of(English).(precise.more)) is(possible) ] ?[ you want.to(help(develop(it))) ]
Jun 02 2002
char[] a = <whatever>; char[] b = <whatever-else>; if ( a == b ) { // this code will be run as if the line above was // if (a.length == b.length && a[0] == b[0]) // so this implies "pos" == "pzz" !! }
That's intended behavior. To get the behaviour you're looking for, use
(that's 3 =).
???????? I thought that == was to compare the references! Since "pos" and "pzz"
be in different points in memory, they cannot have the same internal
and thus the test should fail, right?
The test a[0] == b[0] compares the values in the first element of the two arrays. a[0] === b[0] compares the references to the first element of the two arrays. I think that's right... Alix Pexton...
Jun 02 2002
"anderson" <anderson firestar.com.au> if (a == b) doesn't compare refferences If that's correct, it's going to cause a nightmare in porting. And I know this has readly been fought out. On the otherhand I'd encourage programmers away from using pointers. "Alix Pexton" <Alix seven-point-star.co.uk> wrote in message news:01c20a8a$fec54160$fe247ad5 jpswm...char[] a = <whatever>; char[] b = <whatever-else>; if ( a == b ) { // this code will be run as if the line above was // if (a.length == b.length && a[0] == b[0]) // so this implies "pos" == "pzz" !! }
That's intended behavior. To get the behaviour you're looking for, use
(that's 3 =).
???????? I thought that == was to compare the references! Since "pos" and "pzz"
be in different points in memory, they cannot have the same internal
and thus the test should fail, right?
The test a[0] == b[0] compares the values in the first element of the two arrays. a[0] === b[0] compares the references to the first element of the two arrays. I think that's right... Alix Pexton...
Jun 02 2002
"Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message news:3CFA9191.EE2B49FA deming-os.org...???????? I thought that == was to compare the references!
It used to be. Now it's a deep compare, as everyone convinced me that was a better approach. === is for reference comparisons.
Jun 02 2002
"Walter" <walter digitalmars.com> wrote in message news:adeq4k$80d$1 digitaldaemon.com..."Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message news:3CFA9191.EE2B49FA deming-os.org...???????? I thought that == was to compare the references!
It used to be. Now it's a deep compare, as everyone convinced me that was
better approach. === is for reference comparisons.
Then how does it turn out that "pos" == "psz" (see the first message in the thread)?
Jun 03 2002
"Pavel Minayev" <evilone omen.ru> wrote in message news:adf7ca$o7m$1 digitaldaemon.com..."Walter" <walter digitalmars.com> wrote in message news:adeq4k$80d$1 digitaldaemon.com..."Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message news:3CFA9191.EE2B49FA deming-os.org...???????? I thought that == was to compare the references!
It used to be. Now it's a deep compare, as everyone convinced me that
abetter approach. === is for reference comparisons.
Then how does it turn out that "pos" == "psz" (see the first message in the thread)?
The array lengths and contents match. I guess I don't understand what the question is.
Jun 03 2002
In article <adgof2$2de0$2 digitaldaemon.com>, Walter says...Then how does it turn out that "pos" == "psz" (see the first message in the thread)?
The array lengths and contents match. I guess I don't understand what the question is.
if you see my first posting D only checks the first element in the array if the lengths match. surely it should check all then element for equality before considering them equal. Mike.
Jun 03 2002
<mike.wynn l8night.co.uk> wrote in message news:adh1r5$2ndr$1 digitaldaemon.com...In article <adgof2$2de0$2 digitaldaemon.com>, Walter says...Then how does it turn out that "pos" == "psz" (see the first message in the thread)?
The array lengths and contents match. I guess I don't understand what the question is.
if you see my first posting D only checks the first element in the array if the lengths match. surely it should check all then element for equality before considering them equal.
Yes, it should check all the elements. If it doesn't, it's a bug.
Jun 03 2002
"Walter" <walter digitalmars.com> ha scritto nel messaggio news:adeq4k$80d$1 digitaldaemon.com..."Russ Lewis" <spamhole-2001-07-16 deming-os.org> wrote in message news:3CFA9191.EE2B49FA deming-os.org...???????? I thought that == was to compare the references!
It used to be. Now it's a deep compare, as everyone convinced me that was
better approach. === is for reference comparisons.
This is what we wanted for soo long. Thanks. Ciao
Jun 03 2002