goto... Who uses it?
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That ternary cannot throw. You're thinking of Java and its .equals nonsense. == won't throw for a null.
Learned something new.
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This isn't a programming question. Anyway... I find it useful in very few situations. It can make for cleaner code if used correctly. Of course, it can also be over used.
The only place I can think where it might still be used in modern high-level languages is if one also adheres to the ancient (and out-dated?) principle that a function should have a single exit point. Sometimes making that happen without goto makes for some clunky, hard to read code with multi-level nests of IF blocks. My sig will confirm that I agree with you, though I haven't used goto since I abandoned QuickBasic some 15 years ago, and haven't written assembly in 20+.
If you think 'goto' is evil, try writing an Assembly program without JMP.
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Joe Woodbury wrote:
I would one step further since the ternary test is not only silly, it might throw an exception all on it's own due to text being null. If you KNOW something is "0", why parse it to 0? Why is an empty string valid? Is a null string valid?
I dont know its going to be zero. It could be any number and it will never be null. An empty string is valid because a previous version of this code used them. This version doesnt.
Joe Woodbury wrote:
The code has other problems. Why create the file before you know whether there are any errors?
Because there are terminals that watch for changes in this file. If a parse fails then I have a partially written data file. This will cause several other terminals to report errors.
Joe Woodbury wrote:
Why set totalDelays and value back to zero?
Because totalDelays is for each individual class in dataList. If it's not set back to zero then it will add up across all of the classes in the list. You're making assumptions here. Setting delays to zero is unnecessary. That was left over and can be removed.
Joe Woodbury wrote:
"its" is spelled "it's" in this context, but it should probably read "it was".
Thanks for pointing that out. That grammatical error could cause the entire app to crash and burn. Good catch.
DanielSheets wrote:
I dont know its going to be zero. It could be any number and it will never be null.
An empty string is valid because a previous version of this code used them. This version doesnt.int.TryParse((dgc.MATL.Equals("") ? "0" : dgc.MATL), out value))
In the case of empty string, you know the result will be zero. If this isn't valid for this version, refactor the code and remove the check.
DanielSheets wrote:
Because there are terminals that watch for changes in this file. If a parse fails then I have a partially written data file. This will cause several other terminals to report errors.
You miss my point. You don't need to create the file until you have added up the total count. You can still keep the rename in for the purposes you stated.
DanielSheets wrote:
Because totalDelays is for each individual class in dataList. If it's not set back to zero then it will add up across all of the classes in the list. You're making assumptions here.
Huh? Oh yeah, I was right:
DanielSheets wrote:
Setting delays to zero is unnecessary. That was left over and can be removed.
Fact is, you don't need the goto and were showed why. Instead of taking that and learning (as I did with the ternary and null) you became defensive. Turns out your code needs to be refactored anyway, so why not fix it right?
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The goto is not required, you can always skip around with variable but sometime it's the best solution. In this example the goto is a clear simple example, remove it and you introduce less readable and more complexity.
function BigFunction() {
for (int i =0; i < 100; i++) {
while(true) {
if (...) {
goto DO_SOMETHING_AT_THE_END;
}
}
}DO_SOMETHING_AT_THE_END:
DoSomething();
}I strongly disagree. This calls for splitting the function into two, if not more, pieces and/or rethinking the algorithm. I've seen code like this cause way too many bugs when something is introduced in the middle of BigFunction which doesn't get cleaned up at the end.
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My guess is he goes to those places often and with reason. Thus, other block controls would be more useful. E.g., while he is not at work he is in the bar, etc.
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I wrote assembly for years and never used "goto". :)
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This isn't a programming question. Anyway... I find it useful in very few situations. It can make for cleaner code if used correctly. Of course, it can also be over used.
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I wrote assembly for years and never used "goto". :)
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In SQL - fairly often to jump to the error handler at the end of our sprocs. I'll admit there's no good reason we do this, since it's easy enough for us to avoid this with if statements, but it's a pattern used in our original code and so for consistency we stuck with it:
Create Procedure MyProc as
Begin Tran -- Do stuff... if @@error <> 0 goto errorHandler Commit Tran Return 0errorHandler:
Rollback Tran
Return 1cheers, Chris Maunder The Code Project | Co-founder Microsoft C++ MVP
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DanielSheets wrote:
I dont know its going to be zero. It could be any number and it will never be null.
An empty string is valid because a previous version of this code used them. This version doesnt.int.TryParse((dgc.MATL.Equals("") ? "0" : dgc.MATL), out value))
In the case of empty string, you know the result will be zero. If this isn't valid for this version, refactor the code and remove the check.
DanielSheets wrote:
Because there are terminals that watch for changes in this file. If a parse fails then I have a partially written data file. This will cause several other terminals to report errors.
You miss my point. You don't need to create the file until you have added up the total count. You can still keep the rename in for the purposes you stated.
DanielSheets wrote:
Because totalDelays is for each individual class in dataList. If it's not set back to zero then it will add up across all of the classes in the list. You're making assumptions here.
Huh? Oh yeah, I was right:
DanielSheets wrote:
Setting delays to zero is unnecessary. That was left over and can be removed.
Fact is, you don't need the goto and were showed why. Instead of taking that and learning (as I did with the ternary and null) you became defensive. Turns out your code needs to be refactored anyway, so why not fix it right?
Joe Woodbury wrote:
Huh? Oh yeah, I was right:
You were half right.
Joe Woodbury wrote:
Fact is, you don't need the goto and were showed why. Instead of taking that and learning (as I did with the ternary and null) you became defensive. Turns out your code needs to be refactored anyway, so why not fix it right?
I've not gotten defensive at all? If you think I did, then where? Personally, I like the ternary operator. I like the way it looks and I like the way it works. I'm not a "n00b" programmer by any means. I am, however, completely self taught. I'm also in the process of taking Microsoft certified courses in C# (through the company I work for). Perhaps then I can learn to code to the standards set forth by the majority here. And for the record... Of all of the projects that I've completed here, the code snippet I put here contained the very first use of goto that I've used in years. After thinking about it, its simple and concise. You remind me of a gear snob. In case you're not a musician let me explain that for you. A gear snob is, for example, a guitarist who plays an expensive Fender Strat that looks down on another guitarist that plays a Squier or an Epiphone. You are convinced that goto's and ternary operators are examples of bad programming. So you're condescending to me because I use them. But in the end... I don't care what you think. Your opinion means about as much to me as anybody else's here. And thats exactly what it is. An opinion. How's that for defensive?
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This isn't a programming question. Anyway... I find it useful in very few situations. It can make for cleaner code if used correctly. Of course, it can also be over used.
Twenty years ago i was 10, and learning to program in QBASIC. That was the last time I used GOTO.
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I am not afraid to say I used it at least 4 or 5 times! (in the last 10 years!...) Even once recently! I hate the mindless peer pressure against it, use it even it's ugly if you like! Use whatever makes your code more beautiful! ^^ Just so you know, the (mindless violent) hate against it is based on the following argument: "it's not maintainable" i.e. "it break the flow of the code which should be otherwise obvious" That much is true, long methods with goto label hidden 300 line below are big traps. But this is true of 300 lines method without goto too!!! So, shortly, use it if it's the shorter more expressive solution. If someone doesn't like it, suggest them to fix the code. And choose the most expressive readable code between theirs and yours after that! ;P Anyway, when one use goto? Err... truthfully only one C# exemple comes to my mind (apart switch): how to break out simple of multiple nest loop
for ()
for(..)
for(..)
{
if(condition)
goto exit_loop;
}
exit_loop:;Just so you know, a typical C goto will be for clean up, as in
if (success1) {...}
else goto failure
If (sucess2) { ...}
goto failure
...
return;
failure:but in C# this is more nicely expressed with
try {} catch {} finally {}which doesn't need any gotoMy programming get away... The Blog... DirectX for WinRT/C# since 2013! Taking over the world since 1371!
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This isn't a programming question. Anyway... I find it useful in very few situations. It can make for cleaner code if used correctly. Of course, it can also be over used.
I grew up with gotos, and saw their abuse first hand. Then some luminary someplace realized they were being abused, so decreed them to be evil. Now I keep them hidden away in my basement, away from prying eyes. I don't abuse my gotos like other programmers did, and see that they can still be useful, but I'm too scared of what the other programmers would say to let them out to frolic once in a while. Poor abused little gotos ;(
We can program with only 1's, but if all you've got are zeros, you've got nothing.
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This isn't a programming question. Anyway... I find it useful in very few situations. It can make for cleaner code if used correctly. Of course, it can also be over used.
As a matter of fact, I have to MainTainTheInsane Ball of string of GoTo's in legacy applications that were written decades ago by someone who is long gone. I see it all over and really had a fit when I had to code around them. But since I have been learning COBOL of all flavors, I can now see that it was all they had back then; think of Sequential programing real hard with no bells and whistles like the modern languages have now. After figuring out what one of these old legacy apps does, I have to admire the person/s who had written them; they had to be a lot more creative with so little to work with than what programmers have today to work with. Actually, I have seen some really cool logic using the GoTo; and again, some really insane WTF! stuff. Back in the days, yeah, it was necessary. Todays programming, NOT :)
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Joe Woodbury wrote:
Huh? Oh yeah, I was right:
You were half right.
Joe Woodbury wrote:
Fact is, you don't need the goto and were showed why. Instead of taking that and learning (as I did with the ternary and null) you became defensive. Turns out your code needs to be refactored anyway, so why not fix it right?
I've not gotten defensive at all? If you think I did, then where? Personally, I like the ternary operator. I like the way it looks and I like the way it works. I'm not a "n00b" programmer by any means. I am, however, completely self taught. I'm also in the process of taking Microsoft certified courses in C# (through the company I work for). Perhaps then I can learn to code to the standards set forth by the majority here. And for the record... Of all of the projects that I've completed here, the code snippet I put here contained the very first use of goto that I've used in years. After thinking about it, its simple and concise. You remind me of a gear snob. In case you're not a musician let me explain that for you. A gear snob is, for example, a guitarist who plays an expensive Fender Strat that looks down on another guitarist that plays a Squier or an Epiphone. You are convinced that goto's and ternary operators are examples of bad programming. So you're condescending to me because I use them. But in the end... I don't care what you think. Your opinion means about as much to me as anybody else's here. And thats exactly what it is. An opinion. How's that for defensive?
DanielSheets wrote:
You are convinced that goto's and ternary operators are examples of bad programming.
Good grief. I didn't say ternary operators were bad; I said that since they are no longer needed in your specific code, they can be removed. What I learned was that the code
text == "" ? "0" : ...
does not throw an exception in C# if text is null. My view that gotos are bad is based on years of experience of finding bugs caused by their use (even in assembly where JMPs are a given and cause all sorts of problems when you aren't careful.) Condescension is in the eye of the beholder. In this case, you had a code review, extremely valid suggestions were made on how to improve it. You concede that much of what you are doing isn't needed, but insist on keeping it that way. That's fine, but don't go around blasting everyone for being condescending, a snob or not seeing the full picture.
DanielSheets wrote:
I don't care what you think
Apparently you do else you wouldn't reply. :)
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This isn't a programming question. Anyway... I find it useful in very few situations. It can make for cleaner code if used correctly. Of course, it can also be over used.
I've used goto in C for coroutines in IP or serial protocols, mainly for manually crafting versions of the Protothread / Duffing machine trick. It's also handy in trampoline functions for tail recursion. It can be clearer and more consise than the alternatives.
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In SQL - fairly often to jump to the error handler at the end of our sprocs. I'll admit there's no good reason we do this, since it's easy enough for us to avoid this with if statements, but it's a pattern used in our original code and so for consistency we stuck with it:
Create Procedure MyProc as
Begin Tran -- Do stuff... if @@error <> 0 goto errorHandler Commit Tran Return 0errorHandler:
Rollback Tran
Return 1cheers, Chris Maunder The Code Project | Co-founder Microsoft C++ MVP
The problem with that view ("for consistency") is that you will forever be in the same programming mode. The form of the code should be
if @@error <> 0
BEGIN
Rollback Tran
Return 1
END
else
BEGIN
Commit Tran
Return 0
ENDIn my world there are no exceptions! In C# I do accept the break statement within loops to allow an early escape. But no GOTOs. I programmed during the structured programming discussions in the 1970s. The amount of time required to comprehend GOTO filled code was enormous. And so easily fixed.
Gus Gustafson
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DanielSheets wrote:
You are convinced that goto's and ternary operators are examples of bad programming.
Good grief. I didn't say ternary operators were bad; I said that since they are no longer needed in your specific code, they can be removed. What I learned was that the code
text == "" ? "0" : ...
does not throw an exception in C# if text is null. My view that gotos are bad is based on years of experience of finding bugs caused by their use (even in assembly where JMPs are a given and cause all sorts of problems when you aren't careful.) Condescension is in the eye of the beholder. In this case, you had a code review, extremely valid suggestions were made on how to improve it. You concede that much of what you are doing isn't needed, but insist on keeping it that way. That's fine, but don't go around blasting everyone for being condescending, a snob or not seeing the full picture.
DanielSheets wrote:
I don't care what you think
Apparently you do else you wouldn't reply. :)
I did have valid suggestions. And they were good suggestions. Was this part of your code review?
Joe Woodbury wrote:
"its" is spelled "it's" in this context, but it should probably read "it was".
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"correct use" depends on your definition of "correct". However, the main point is that even if at first it makes sense, or even simplifies code, it suffers from the lack of long-tem maintainability: Unlike other control statements, goto lacks an associated block of control, and thus makes it considerably harder to detect or verify the effect of any change you make to code that may or may not be executed, once or repeatedly, depending on goto statements in potentially several entirely different place(s). Goto would be much less of a problem if jump labels weren't self-declaring and global: if you could localize the use of a label like variable names, that would greatly restrict the potential (ab)use of goto commands, and thus ease the effort to understand the code and verify changes.
Stefan_Lang wrote:
"correct use" depends on your definition of "correct". However, the main point is that even if at first it makes sense, or even simplifies code, it suffers from the lack of long-tem maintainability:
Just to make it clear I have 40+ years of programming experience and I started before OO existed and used languages where one had to use goto along with using languages where goto didn't exist. And a number in between. I understand not only how goto can be misused but how any number of constructs can be used incorrectly. I also understand how absolutes are never that. (Where the former is a technical point and the latter part is not.) And that is the context in which I made my response.
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Eddy Vluggen wrote:
Readable code leads to maintainable projects. The better a project can be maintained, the more chances it will survive in the long run.
.... which is completely offset by his use of 'goto'.
If it's not broken, fix it until it is
Kevin Marois wrote:
.... which is completely offset by his use of 'goto'.
Nope. The code as presented was readable and was maintainable. Given that maintenance is a proven and known expense then I would much rather have the code that was presented versus some esoteric trick that is technically correct but neither readable nor maintainable.