473,706 Members | 2,092 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

goto

Hi,
I know I know its notoriously bad! I don't want to use it. I was wondering,
does it still exist? If it does, I really don't understand how!? like what
happens if you just goto halfway through a function (no objects properly
constructed!) , or a constructor itself??
Just intrigued!!

Mike
Jul 23 '05 #1
36 6732
* Michael:

I know I know its notoriously bad! I don't want to use it. I was wondering,
does it still exist?
Yes.

If it does, I really don't understand how!?
Like always.

like what
happens if you just goto halfway through a function (no objects properly
constructed!) ,
That is forbidden by §6.6.4/3; it won't or shouldn't compile.

or a constructor itself??
?

Just intrigued!!


As you learn more you'll find many more unsafe constructs, in all languages.

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?
Jul 23 '05 #2
Michael wrote:
I know I know its notoriously bad!
Long functions are bad. Short ones have no reason to use 'goto', and thus
'goto' is relatively harmless.
I don't want to use it. I was wondering,
does it still exist? If it does, I really don't understand how!? like what
happens if you just goto halfway through a function (no objects properly
constructed!) , or a constructor itself??


Ordinarily, one should not learn C++ laws via "but my compiler likes it".

In this case, a little VC++ experiment is useful:

goto bar;
string foo;
bar:;

error C2362: initialization of 'foo' is skipped by 'goto bar'

The language designers took care of it. With no legacy C constructors to
support, they ordained compilers reject (relatively) non-structured 'goto'
abuses.

--
Phlip
http://industrialxp.org/community/bi...UserInterfaces
Jul 23 '05 #3

"Alf P. Steinbach" <al***@start.no > wrote in message
news:42******** ********@news.i ndividual.net.. .
* Michael:

I know I know its notoriously bad! I don't want to use it. I was wondering, does it still exist?
Yes.

If it does, I really don't understand how!?


Like always.

like what
happens if you just goto halfway through a function (no objects properly
constructed!) ,


That is forbidden by §6.6.4/3; it won't or shouldn't compile.

so what are the limits on what you can 'goto' 'to' ?
local scope?

or a constructor itself??
?

Just intrigued!!


As you learn more you'll find many more unsafe constructs, in all

languages.
--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

Jul 23 '05 #4
* Michael:

* Alf P. Steinbach:
* Michael:

I know I know its notoriously bad! I don't want to use it. I was
wondering, does it still exist?


Yes.

If it does, I really don't understand how!?


Like always.

like what
happens if you just goto halfway through a function (no objects properly
constructed!) ,


That is forbidden by §6.6.4/3; it won't or shouldn't compile.

so what are the limits on what you can 'goto' 'to' ?
local scope?


Quoting the standard: "It is possible to transfer into a block, but not in a
way that bypasses declarations with initialization. "

Btw., don't quote things you don't reply to or irrelevant to your reply;
snipped further quoting.

Download and install <url: http://home.in.tum.de/~jain/software/oe-quotefix/>.

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?
Jul 23 '05 #5
"Michael" <sl***********@ hotmail.com> wrote in
news:d1******** **@sparta.btint ernet.com:
Hi,
I know I know its notoriously bad! I don't want to use it. I was
wondering, does it still exist? If it does, I really don't understand
how!? like what happens if you just goto halfway through a function
(no objects properly constructed!) , or a constructor itself??
Just intrigued!!


Yes goto still exists.

The type of goto you describe is ill-formed. See section 6.7(3) of the
Holy Standard :)
Jul 23 '05 #6
Michael wrote:
Hi,
I know I know its notoriously bad! I don't want to use it. I was wondering,
does it still exist? If it does, I really don't understand how!?

Yes it exists. Assume by "how" you mean "why". goto is extensively used
in machine-produced efficient C++ code.

--
Ioannis Vranos

http://www23.brinkster.com/noicys
Jul 23 '05 #7
Ioannis Vranos wrote:
Yes it exists. Assume by "how" you mean "why". goto is extensively used
in machine-produced efficient C++ code.


Please note Ioannis did not say "goto is efficient". It might be more
efficient than a well-structured function call; it might not.

Under the theory that a function takes time pushing variables onto a stack,
'goto' might generate a single branch opcode. However, that 'goto' might
live in a function that's now long enough to overflow the CPU cache. Several
small functions might have fit in the cache, making their specific function
calls faster.

--
Phlip
http://industrialxp.org/community/bi...UserInterfaces
Jul 23 '05 #8
On Thu, 24 Mar 2005 23:53:37 +0000 (UTC), "Michael"
<sl***********@ hotmail.com> wrote:
I know I know its notoriously bad! I don't want to use it.


Why not? Goto is very useful since there is not labelled break. When
you have nested for in another for /for example/ the easiest way /and
elegant too/ to break from the external one is to use goto.

have a nice day
bye
--
Maciej "MACiAS" Pilichowski http://bantu.fm.interia.pl/

M A R G O T --> http://www.margot.cad.pl/
automatyczny t³umacz (wczesna wersja rozwojowa) angielsko-polski
Jul 23 '05 #9
Maciej Pilichowski wrote:
Michael wrote:
I know I know its notoriously bad! I don't want to use it.


Why not? Goto is very useful since there is not labelled break. When
you have nested for in another for /for example/ the easiest way /and
elegant too/ to break from the external one is to use goto.


or return.

Why is your function so long?

--
Phlip
http://industrialxp.org/community/bi...UserInterfaces
Jul 23 '05 #10

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

30
4266
by: Hayri ERDENER | last post by:
hi, what is the equivalent of C languages' goto statement in python? best regards
51
13368
by: WindAndWaves | last post by:
Can anyone tell me what is wrong with the goto command. I noticed it is one of those NEVER USE. I can understand that it may lead to confusing code, but I often use it like this: is this wrong????? Function x select case z
37
3248
by: Tim Marshall | last post by:
From http://www.mvps.org/access/tencommandments.htm 9th item: Thou shalt not use "SendKeys", "Smart Codes" or "GoTo" (unless the GoTo be part of an OnError process) for these will lead you from the path of righteousness. What about also using it as a means of exiting a procedure?
52
21932
by: Rick | last post by:
Hi, For portability, can an issue arise if we use while(1) for an infinite loop in C? If so, should we then use for(;;)? Thanks, Rick
45
2713
by: Debashish Chakravarty | last post by:
K&R pg.66 describes two situations when using goto makes sense. Has anyone here come across situations where using goto provided the most elegant solution. -- http://www.kashmiri-pandit.org/atrocities/index.html
77
4006
by: M.B | last post by:
Guys, Need some of your opinion on an oft beaten track We have an option of using "goto" in C language, but most testbooks (even K&R) advice against use of it. My personal experience was that goto sometimes makes program some more cleaner and easy to understand and also quite useful (in error handling cases). So why goto is outlawed from civilized c programmers community. is there any technical inefficiency in that.
34
26641
by: electrician | last post by:
Perl has it, Basic has it, Fortran has it. What is so difficult about creating a goto command for JavaScript. Just set up a label and say go to it.
3
2187
by: electrician | last post by:
Yes, no GOTO. This is a major blunder on part of the creators of these tools. GOTO gives the programmer the absolute control over the program. Yes, no matter what, a GOTO sends the program to where YOU want and takes the power away from the mean spirited CREATORS. Yes, even GOD gave us free will! But the creators of JavaScript have decided they will forever interfere in how YOU program. THEY have decided to keep GOTO to themselves...
17
2608
by: SoftEast | last post by:
Hi Buddies, I have read a lot of stuffs regarding not using GOTO statements to opt a good programming style http://david.tribble.com/text/goto.html]. Can anybody give a particular lines of code which shows harmfullness of GOTO. SoftEast...
59
5042
by: raashid bhatt | last post by:
why are GOTO's not used they just a simple JMP instructions what's bad about them
0
8697
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
0
9287
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
0
9157
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
1
9056
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
8999
tracyyun
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
1
6615
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms. Adolph will...
0
5939
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
4454
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
1
3150
by: 6302768590 | last post by:
Hai team i want code for transfer the data from one system to another through IP address by using C# our system has to for every 5mins then we have to update the data what the data is updated we have to send another system

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.