goto statement
-
Why many hate this statement and do not advise using it! I used it when I started programming with BASIC and GWBASIC. It is also found in the C#. Troubles are based on the programmer who is misusing it.
In the olden day (60's and 70's mostly), goto was abused as much as (or more than) var is today. Some programmers resisted this, lead by E. Dijkstra. They gathered momentum, lost their rationality, became zealous, succeeded in converting all new and most old programmers to their Holy Cause. As a result, The Hivemind took the position that all use of goto is nothing less than Pure Evil(tm), and now prefers to use highly obfuscated but structured control flow where a simple goto would have solved the problem in a simpler way. The Hivemind, ever hypocritical, also suggests refucktoring "nested loops where you exit both of them from the inner loop" to a confusingly-named and nonsensical-on-its-own function with multiple returns, a practice that it itself also denounces.
-
Because in nearly every case I have seen of it's use in C# or C++ it has been unnecessary, and only served to both confuse the code and show that the person who used it did not understand what he was doing.
gotois not evil - but it is a "rule breaker" in that it violates all the principles of good code design and so using it should only be done with care. The problem is that it it taught on courses by lazy tutors as an easy way to get them started and then gets abused later because the students consider it "Normal" and don't learn to structure code well in the first place as a result. If you had grown up withGOTOas pretty much the only form of flow control (as I did) you would probably understand how easy it is to create impenetrable code with it, and why it should be discouraged until the coder is experienced enough to know when it is appropriate. About five years of "real" coding should be enough. But by then, he is probably experienced enough to know that there are probably better ways to achieve the same result...The only instant messaging I do involves my middle finger. English doesn't borrow from other languages. English follows other languages down dark alleys, knocks them over and goes through their pockets for loose grammar.
That's the usual reasoning and perfectly ok in most cases. What if I need to squeeze out a better performance? Readability and maintainability now are secondary. I have done this often enough in the past and still do it today. Writing software is not a religion and mindlessly reciting and enforcing rules does not help at all. The rules may have good reasons, but you must always understand their goals. Break them if your goals happen to be different.
Sent from my BatComputer via HAL 9000 and M5
-
In the olden day (60's and 70's mostly), goto was abused as much as (or more than) var is today. Some programmers resisted this, lead by E. Dijkstra. They gathered momentum, lost their rationality, became zealous, succeeded in converting all new and most old programmers to their Holy Cause. As a result, The Hivemind took the position that all use of goto is nothing less than Pure Evil(tm), and now prefers to use highly obfuscated but structured control flow where a simple goto would have solved the problem in a simpler way. The Hivemind, ever hypocritical, also suggests refucktoring "nested loops where you exit both of them from the inner loop" to a confusingly-named and nonsensical-on-its-own function with multiple returns, a practice that it itself also denounces.
harold aptroot wrote:
The Hivemind, ever hypocritical, also suggests refucktoring "nested loops where you exit both of them from the inner loop" to a confusingly-named and nonsensical-on-its-own function with multiple returns, a practice that it itself also denounces.
You mean the old story recursion vs. iteration? The stuff some eggheads traditionally use to torture students in their first semester? :)
Sent from my BatComputer via HAL 9000 and M5
-
That's the usual reasoning and perfectly ok in most cases. What if I need to squeeze out a better performance? Readability and maintainability now are secondary. I have done this often enough in the past and still do it today. Writing software is not a religion and mindlessly reciting and enforcing rules does not help at all. The rules may have good reasons, but you must always understand their goals. Break them if your goals happen to be different.
Sent from my BatComputer via HAL 9000 and M5
If you know what you are doing, then you have enough experience to know when it is appropriate to use. I completely agree with you: it's a useful tool. But like all tools, you have to know how and when to use it. Performance tuning (as you know well) needs more than just "quick code" - it needs a careful look at the whole of what is occurring and frequently a change of algorithm as well as hand-tuning of the code. And if you know what you are doing enough to do that, you understand the effects of your changes. Even Dijkstra said that it has it's place, but that use must be tempered with knowledge of the effects. Obligatory XKCD reference[^]
The only instant messaging I do involves my middle finger. English doesn't borrow from other languages. English follows other languages down dark alleys, knocks them over and goes through their pockets for loose grammar.
-
Very well put! The only goto-like statement I use is a
breakstatement. However even at the beginning of coding in .Net I was uncomfortable using it, shaping my logic so that I did not need to use it. At university, back in 1988, I was taught never to use a goto statement - one very rare case necessitating its use in COBOL being the exception.“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
*shudder* First language I was taught, that. Then FORTRAN to follow, which was a breath of (what seemed like structured at the time) fresh air in comparison! :laugh:
The only instant messaging I do involves my middle finger. English doesn't borrow from other languages. English follows other languages down dark alleys, knocks them over and goes through their pockets for loose grammar.
-
I didn't even realise that C# had a goto statement! Now that I do know this I will now use it in a profligate manner - mwahahahahah!
“That which can be asserted without evidence, can be dismissed without evidence.”
― Christopher Hitchens
You have just gained a level. Instead of blindly following some master wizard's rules, you now have begun to make your own. Before you know it you will zap your opponents with pointy pointers and even manage memory yourself. I actually prefer working with people who occasionally contemplate to break the rules instead of reciting them. :)
Sent from my BatComputer via HAL 9000 and M5
-
harold aptroot wrote:
The Hivemind, ever hypocritical, also suggests refucktoring "nested loops where you exit both of them from the inner loop" to a confusingly-named and nonsensical-on-its-own function with multiple returns, a practice that it itself also denounces.
You mean the old story recursion vs. iteration? The stuff some eggheads traditionally use to torture students in their first semester? :)
Sent from my BatComputer via HAL 9000 and M5
-
Why many hate this statement and do not advise using it! I used it when I started programming with BASIC and GWBASIC. It is also found in the C#. Troubles are based on the programmer who is misusing it.
I've made my living programming since 1980. I've written millions of lines of code in everything from C#, C++, C, to several assembly languages. I've been writing C# since 2008. I've never needed to use
goto. I've been writing C++ since 2000. I've never needed to usegoto. My C code, written from 1990 to around 2002, usedgotosolely for exception handling. The Microsoft and Watcom C compilers at the time didn't support exceptions in a robust fashion.Tarek Elqusi wrote:
Troubles are based on the programmer who is misusing it
While that statement is true, the converse is not. I've never found a case in modern times where
gotowas necessary. There is always a structured alternative. If a programmer is good enough, they will not needgoto.Software Zen:
delete this; -
Because in nearly every case I have seen of it's use in C# or C++ it has been unnecessary, and only served to both confuse the code and show that the person who used it did not understand what he was doing.
gotois not evil - but it is a "rule breaker" in that it violates all the principles of good code design and so using it should only be done with care. The problem is that it it taught on courses by lazy tutors as an easy way to get them started and then gets abused later because the students consider it "Normal" and don't learn to structure code well in the first place as a result. If you had grown up withGOTOas pretty much the only form of flow control (as I did) you would probably understand how easy it is to create impenetrable code with it, and why it should be discouraged until the coder is experienced enough to know when it is appropriate. About five years of "real" coding should be enough. But by then, he is probably experienced enough to know that there are probably better ways to achieve the same result...The only instant messaging I do involves my middle finger. English doesn't borrow from other languages. English follows other languages down dark alleys, knocks them over and goes through their pockets for loose grammar.
You mean you are 'grown up'! Can't believe that... :laugh: But as for the rest I agree with you - don't break rules just for breaking them...
I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is (V).
-
If you know what you are doing, then you have enough experience to know when it is appropriate to use. I completely agree with you: it's a useful tool. But like all tools, you have to know how and when to use it. Performance tuning (as you know well) needs more than just "quick code" - it needs a careful look at the whole of what is occurring and frequently a change of algorithm as well as hand-tuning of the code. And if you know what you are doing enough to do that, you understand the effects of your changes. Even Dijkstra said that it has it's place, but that use must be tempered with knowledge of the effects. Obligatory XKCD reference[^]
The only instant messaging I do involves my middle finger. English doesn't borrow from other languages. English follows other languages down dark alleys, knocks them over and goes through their pockets for loose grammar.
OriginalGriff wrote:
it needs a careful look at the whole of what is occurring and frequently a change of algorithm as well as hand-tuning of the code
I've done some minor bits of optimization on occasion. I've never needed
gotoas part of any hand-tuning. Algorithm improvements and refactoring are generally the way to go for me.Software Zen:
delete this; -
You mean you are 'grown up'! Can't believe that... :laugh: But as for the rest I agree with you - don't break rules just for breaking them...
I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is (V).
Good grief no! I'm just old.
The only instant messaging I do involves my middle finger. English doesn't borrow from other languages. English follows other languages down dark alleys, knocks them over and goes through their pockets for loose grammar.
-
Why many hate this statement and do not advise using it! I used it when I started programming with BASIC and GWBASIC. It is also found in the C#. Troubles are based on the programmer who is misusing it.
Ahh... This is one of my favourite subjects. I think we went to the total unbalance of the overpopulation of gotos of BASIC to the total unbalance of goto starvation on structured languajes. A goto is perfect for some weird situations. Imagine your fiancee calls you at work, because you've won severals milions on LOTO. May be your exit from work will be no too structured, and so must be. In others words goto deals well with some fatal error situatios, a glance at linux kernel code shows this. What? I'm getting seriuous. goto minibar.
-
Ahh... This is one of my favourite subjects. I think we went to the total unbalance of the overpopulation of gotos of BASIC to the total unbalance of goto starvation on structured languajes. A goto is perfect for some weird situations. Imagine your fiancee calls you at work, because you've won severals milions on LOTO. May be your exit from work will be no too structured, and so must be. In others words goto deals well with some fatal error situatios, a glance at linux kernel code shows this. What? I'm getting seriuous. goto minibar.
If you don't think that
GOTOis an interesting topic of conversation, try the Duff device. http://www.lysator.liu.se/c/duffs-device.html[^]Pablo. "Accident: An inevitable occurrence due to the action of immutable natural laws." (Ambrose Bierce, circa 1899). "You are to act in the light of experience as guided by intelligence" (Rex Stout, "In the Best Families", 1950).
-
If you don't think that
GOTOis an interesting topic of conversation, try the Duff device. http://www.lysator.liu.se/c/duffs-device.html[^]Pablo. "Accident: An inevitable occurrence due to the action of immutable natural laws." (Ambrose Bierce, circa 1899). "You are to act in the light of experience as guided by intelligence" (Rex Stout, "In the Best Families", 1950).
:thumbsup: I'd never seen that before. Awesome.
-
Ahh... This is one of my favourite subjects. I think we went to the total unbalance of the overpopulation of gotos of BASIC to the total unbalance of goto starvation on structured languajes. A goto is perfect for some weird situations. Imagine your fiancee calls you at work, because you've won severals milions on LOTO. May be your exit from work will be no too structured, and so must be. In others words goto deals well with some fatal error situatios, a glance at linux kernel code shows this. What? I'm getting seriuous. goto minibar.
altomaltes wrote:
your exit from work will be no too structured
That's an interrupt.
-
Why many hate this statement and do not advise using it! I used it when I started programming with BASIC and GWBASIC. It is also found in the C#. Troubles are based on the programmer who is misusing it.
It's fine when it's the only tool in the box (very old BASIC, DCL, DOS batch files, etc.), but I've never needed it in languages that support structured programming.
-
If you don't think that
GOTOis an interesting topic of conversation, try the Duff device. http://www.lysator.liu.se/c/duffs-device.html[^]Pablo. "Accident: An inevitable occurrence due to the action of immutable natural laws." (Ambrose Bierce, circa 1899). "You are to act in the light of experience as guided by intelligence" (Rex Stout, "In the Best Families", 1950).
Could this be written by C# ?
-
Because in nearly every case I have seen of it's use in C# or C++ it has been unnecessary, and only served to both confuse the code and show that the person who used it did not understand what he was doing.
gotois not evil - but it is a "rule breaker" in that it violates all the principles of good code design and so using it should only be done with care. The problem is that it it taught on courses by lazy tutors as an easy way to get them started and then gets abused later because the students consider it "Normal" and don't learn to structure code well in the first place as a result. If you had grown up withGOTOas pretty much the only form of flow control (as I did) you would probably understand how easy it is to create impenetrable code with it, and why it should be discouraged until the coder is experienced enough to know when it is appropriate. About five years of "real" coding should be enough. But by then, he is probably experienced enough to know that there are probably better ways to achieve the same result...The only instant messaging I do involves my middle finger. English doesn't borrow from other languages. English follows other languages down dark alleys, knocks them over and goes through their pockets for loose grammar.
After using FORTRAN for far too long (up to Fortran-77) with it's use of GOTO and, even more obfuscating, computed gotos, I started using C. However, I was self-taught and was therefore never was taught by anybody that there was a GOTO in the language! I used C for several years, then C++ and now I am firmly in the C# camp. I personally have never used GOTO in any of that code and was shocked one day to find a GOTO residing in someone else's code I had to fix. It was a revelation as big as finding out that one is allowed to use guns during a penalty kick-off. I didn't even know the syntax existed! The whole point of my argument is that I never felt the need for a GOTO at any time, ever - so I didn't miss it. I didn't make artificial constructs to get around using GOTO; I didn't deliberately re-write my code to avoid using one; it just came about naturally that I didn't ever need one. Having said that, I am sure that GOTO may be useful in some real-time code somewhere for performance reasons. My real bug-bear is with multiple RETURNs. I do actually go out of my way to avoid them and re-write them out of existence wherever I find them. I have not yet found any instance where multiple RETURNs from a method has been necessary. I miss allowing the drop through of CASE statements in a switch that has been removed in C#, forcing me to put BREAK at the end of each part and leading me to repeat code unnecessarily now and then so I am not always in favour of compiler/syntax restrictions in a language but I wish multiple RETURNs had been proscribed in the same way.
- I would love to change the world, but they won’t give me the source code.
-
After using FORTRAN for far too long (up to Fortran-77) with it's use of GOTO and, even more obfuscating, computed gotos, I started using C. However, I was self-taught and was therefore never was taught by anybody that there was a GOTO in the language! I used C for several years, then C++ and now I am firmly in the C# camp. I personally have never used GOTO in any of that code and was shocked one day to find a GOTO residing in someone else's code I had to fix. It was a revelation as big as finding out that one is allowed to use guns during a penalty kick-off. I didn't even know the syntax existed! The whole point of my argument is that I never felt the need for a GOTO at any time, ever - so I didn't miss it. I didn't make artificial constructs to get around using GOTO; I didn't deliberately re-write my code to avoid using one; it just came about naturally that I didn't ever need one. Having said that, I am sure that GOTO may be useful in some real-time code somewhere for performance reasons. My real bug-bear is with multiple RETURNs. I do actually go out of my way to avoid them and re-write them out of existence wherever I find them. I have not yet found any instance where multiple RETURNs from a method has been necessary. I miss allowing the drop through of CASE statements in a switch that has been removed in C#, forcing me to put BREAK at the end of each part and leading me to repeat code unnecessarily now and then so I am not always in favour of compiler/syntax restrictions in a language but I wish multiple RETURNs had been proscribed in the same way.
- I would love to change the world, but they won’t give me the source code.
I disagree to an extent with you about multiple returns: I'd rather see a method with validations at the top, each with it's own error report and a return than some "faffing about" code to avoid it. I just think it makes the code look cleaner.
The only instant messaging I do involves my middle finger. English doesn't borrow from other languages. English follows other languages down dark alleys, knocks them over and goes through their pockets for loose grammar.
-
I disagree to an extent with you about multiple returns: I'd rather see a method with validations at the top, each with it's own error report and a return than some "faffing about" code to avoid it. I just think it makes the code look cleaner.
The only instant messaging I do involves my middle finger. English doesn't borrow from other languages. English follows other languages down dark alleys, knocks them over and goes through their pockets for loose grammar.
I always structure things to do validation at the top a bit like:
private bool SomeMethod(string someStingArg, int anIntArg)
{
bool workedOK = false;
if (IsValidForThisFunction(somString) && IsAlsoValid(anIntArg))
{
// Do stuff here...
workedOK = true;
}
return workedOK;
}...or, if individual validations are necessary...
private bool SomeMethod(string someStingArg, int anIntArg)
{
bool workedOK = false;
if (IsValidForThisFunction(somString))
{
if (IsAlsoValid(anIntArg))
{
// Do stuff here...
workedOK = true;
}
}
return workedOK;
}That way I still have only one exit - and I have all the validations at the top. Obviously there are try...catch blocks involved but I wanted to put a simple layout.
- I would love to change the world, but they won’t give me the source code.
