-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Chuck,
On 2/16/2009 5:19 PM, Caldarale, Charles R wrote: >> From: Christopher Schultz [mailto:ch...@christopherschultz.net] >> Subject: Re: [OT] of the different methods to get a user-id >> >> For instance. >> i = i++ >> >> yields different results depending on what language >> you are using. C and Java produce different outputs >> (which really surprised me!). > > Java explicitly defines the behavior of the above statement, whereas > the C standard does not, and leaves it up to the implementation to > decide what to do. However, on almost every platform I have access to > right at this moment (Windows, Linux, proprietary), printing the value > of i after your test statement in both C and Java displayed the original > value of i (as expected), not the increment thereof. $ java -version java version "1.5.0_13" Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_13-b05) Java HotSpot(TM) Client VM (build 1.5.0_13-b05, mixed mode) $ javac PostIncrementTest.java (see below) $ java PostIncrementTest 0 0 0 $ cc --version gcc (GCC) 4.1.2 (Gentoo 4.1.2 p1.1) Copyright (C) 2006 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. $ cc -o post_increment_test post_increment_test.c (see below) $ ./post_increment_test 0 0 1 $ I'm not sure what to say. Here are the sources: post_increment_test.c: #include <stdio.h> int main() { printf("%d %d %d\n", test1(), test2(), test3()); return 0; } int test1() { int i = 0; return i++; } int test2() { int i = 0; return (i++); } int test3() { int i = 0; i = i++; return i; } PostIncrementTest.java: public class PostIncrementTest { public static void main(String[] args) { System.out.println(test1()); System.out.println(test2()); System.out.println(test3()); } public static int test1() { int i=0; return i++; } public static int test2() { int i=0; return (i++); } public static int test3() { int i=0; i = i++; return i; } } > The one problematic environment that gave the unexpected answer was > Visual C++ 6.0 on Windows (gee, Microsoft ignores standard practice? > who would a-thunk it); gcc on Windows worked properly. Do you mean gcc on win32 worked as you expected? As you said, C does not define this behavior, so "proper" is in the eye... - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkmZ6l4ACgkQ9CaO5/Lv0PB+RQCffUOOV9Lv6tuBfSoG1e5mcvmm YA4AoJoFhjoMaIbxCwqe6nxyPfh7fhcX =0Dpi -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
