Straw Poll: Return True or False?
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Christian Graus wrote:
Otherwise, when would you return false ?
What if an incorrect parameter was passed (eg item # -1), or the collection was actually a database table and you coldn't open the table? False could mean "Something bad happened and there's no way the item could be removed", and true "The item is no longer there".
cheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
If you're passing in an item index, then false is going to denote that item index did not exist. If you're passing in a key to remove, then false will indicate the key did not exist. If there's any other reason for failure, then it depends on how specific you want to be. Do you need an enum, or is false OK for all failures ? Either way, true seems wrong to me.
Christian Graus - Microsoft MVP - C++ Metal Musings - Rex and my new metal blog "I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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TRUE, for exactly the reason you gave. if the caller needed to know that the item wasn't in the list to begin with, and needs to act on that info, he should've called collection.Find(item) beforehand.
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When would you return false, in a method that does nothing more than remove an item from a list ? How could removing an item from a list fail, so that the item is still there ?
Christian Graus - Microsoft MVP - C++ Metal Musings - Rex and my new metal blog "I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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Here's a philosophical question: If you have a function that is meant to delete an item from a collection and the item you wish to delete doesn't exist, do you: 1. Return TRUE since the final outcome (not having that item) has been fulfilled, or 5. Return FALSE because since the function couldn't find the item, it couldn't actually delete it. Vote now.
cheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
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Here's a philosophical question: If you have a function that is meant to delete an item from a collection and the item you wish to delete doesn't exist, do you: 1. Return TRUE since the final outcome (not having that item) has been fulfilled, or 5. Return FALSE because since the function couldn't find the item, it couldn't actually delete it. Vote now.
cheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
Chris Maunder wrote:
If you have a function that is meant to delete an item from a collection and the item you wish to delete doesn't exis
ArgumentOutOfRangeException[^] The exception that is thrown when the value of an argument is outside the allowable range of values as defined by the invoked method.
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.(John 3:16) :badger:
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Here's a philosophical question: If you have a function that is meant to delete an item from a collection and the item you wish to delete doesn't exist, do you: 1. Return TRUE since the final outcome (not having that item) has been fulfilled, or 5. Return FALSE because since the function couldn't find the item, it couldn't actually delete it. Vote now.
cheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
Neither. As a general rule, I don't like methods with side effects to return values. That's not to say that I don't break this rule from time to time, but I try to avoid it if possible.
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I don't see where I said return true in both cases. That would be stupid. If you are going to return the same result in either case make it void and don't return anything.
My name is Maximus Decimus Meridius, Commander of the Armies of the North, General of the Felix Legions, loyal servant to the true emperor, Marcus Aurelius. Father to a murdered process, husband to a murdered thread. And I will have my affinity, in this life or the next. - Gladiator. (Okay, not quite Gladiator but close.) I work to live. I do not live to work. My clients do not seem capable of grasping this fact. Ancient of days! august Athena! where, Where are thy men of might? - Lord Byron
The question was: "If you have a function that is meant to delete an item from a collection and the item you wish to delete doesn't exist, do you: 1. Return TRUE since the final outcome (not having that item) has been fulfilled, or" You said you voted '1'. Surely if I call delete, and the item DOES exist, it's going to return true ? And so, if it doesn't exist, it's also going to return true. When will it return false ? I'm not sure I see how removing an item from a list is going to fail, when the item is in there. Or am I missing something ?
Christian Graus - Microsoft MVP - C++ Metal Musings - Rex and my new metal blog "I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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Here's a philosophical question: If you have a function that is meant to delete an item from a collection and the item you wish to delete doesn't exist, do you: 1. Return TRUE since the final outcome (not having that item) has been fulfilled, or 5. Return FALSE because since the function couldn't find the item, it couldn't actually delete it. Vote now.
cheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
Generally I wouldnt return anything. The contract for a delete method is generally that the item identified by the params to the call will not exist in the collection after the call. If it didnt exist it the first place then them method has still done its job. Any other error I'd report via an exception. If the client code needs to know if the object actually existed in the collection prior to the delete method it should use a find method. An exception to this would be where performace is critical and calling a find before a delete would result in two identical costly lookups in the collection in which case I'd return true if it was found and deleted
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Chris Maunder wrote:
If you have a function that is meant to delete an item from a collection and the item you wish to delete doesn't exis
ArgumentOutOfRangeException[^] The exception that is thrown when the value of an argument is outside the allowable range of values as defined by the invoked method.
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.(John 3:16) :badger:
That's a bit of a large hammer to weild. What if you vaguely expect an item to be there but another process has removed it just before you do. Is an exception a good idea, considering that in the end it's not so much an error, but more of a "oh well" thing.
throw new NotThereShrugException();cheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
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Here's a philosophical question: If you have a function that is meant to delete an item from a collection and the item you wish to delete doesn't exist, do you: 1. Return TRUE since the final outcome (not having that item) has been fulfilled, or 5. Return FALSE because since the function couldn't find the item, it couldn't actually delete it. Vote now.
cheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
Chris Maunder wrote:
meant to delete an item
The function failed. It must therefore return false. I have spoken. /ravi
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The question was: "If you have a function that is meant to delete an item from a collection and the item you wish to delete doesn't exist, do you: 1. Return TRUE since the final outcome (not having that item) has been fulfilled, or" You said you voted '1'. Surely if I call delete, and the item DOES exist, it's going to return true ? And so, if it doesn't exist, it's also going to return true. When will it return false ? I'm not sure I see how removing an item from a list is going to fail, when the item is in there. Or am I missing something ?
Christian Graus - Microsoft MVP - C++ Metal Musings - Rex and my new metal blog "I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
I think the last 10 words of my last sentence clear that up. "...then you'd want to have a false result..." :-D
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Chris Maunder wrote:
meant to delete an item
The function failed. It must therefore return false. I have spoken. /ravi
What if it can't find the item but instead returns a ham sandwich?
throw new BribeRaviWithGoodiesExceptioncheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
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I think the last 10 words of my last sentence clear that up. "...then you'd want to have a false result..." :-D
Yeah, you said 'if you want to do additional processing'. Assuming you do not, assuming the method just does the remove and returns true if the item is removed, or did not exist, then when will it return false, in that instance ?
Christian Graus - Microsoft MVP - C++ Metal Musings - Rex and my new metal blog "I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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When would you return false, in a method that does nothing more than remove an item from a list ? How could removing an item from a list fail, so that the item is still there ?
Christian Graus - Microsoft MVP - C++ Metal Musings - Rex and my new metal blog "I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
you don't return false. actually, you don't return anything. but that wasn't an option. if you can't delete it (because you're about to blow the stack or something), throw an exception. i'm sure you can write an app that needs Delete to tell you if the object was deleted or not (and i probably have), but if we're talking about the Platonic Ideal Delete, i don't think it should tell you anything besides "don't know why, but total failure is imminent".
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Christian Graus wrote:
Otherwise, when would you return false ?
What if an incorrect parameter was passed (eg item # -1), or the collection was actually a database table and you coldn't open the table? False could mean "Something bad happened and there's no way the item could be removed", and true "The item is no longer there".
cheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
Then an exception would be thrown (or passed along).
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What if it can't find the item but instead returns a ham sandwich?
throw new BribeRaviWithGoodiesExceptioncheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
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Yeah, you said 'if you want to do additional processing'. Assuming you do not, assuming the method just does the remove and returns true if the item is removed, or did not exist, then when will it return false, in that instance ?
Christian Graus - Microsoft MVP - C++ Metal Musings - Rex and my new metal blog "I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
Christian Graus wrote:
Assuming you do not, assuming the method just does the remove and returns true if the item is removed, or did not exist, then when will it return false, in that instance ?
Assuming you don't want to do additional processing then my vote for 1.0 applies and that's that. But really... if your not going to do anything else you don't need a result do you? Make it void unless you intend to throw an error in the case it finds nothing. If you don't wish to do additional processing you don't need any return just void it.
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That's a bit of a large hammer to weild. What if you vaguely expect an item to be there but another process has removed it just before you do. Is an exception a good idea, considering that in the end it's not so much an error, but more of a "oh well" thing.
throw new NotThereShrugException();cheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
Chris Maunder wrote:
What if you vaguely expect an item to be there but another process has removed it just before you do. Is an exception a good idea, considering that in the end it's not so much an error, but more of a "oh well" thing.
It depends of the level of control that you desires. Look: TRUE: The item was in the list, and the method deleted it successfully. FALSE: The item was in the list, and the method cannot delete it by some dummy reason. EXCEPTION: The item wasn't in the list, the method cannot start the process of deletion because the argument was invalid. If the method started and the item exists, then you lock the collection and try delete it. Just my two cents. :)
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.(John 3:16) :badger:
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ok, how about a hamburger, instead?
Silence is the voice of complicity. Strange women lying in ponds distributing swords is no basis for a system of government. -- monty python Might I suggest that the universe was always the size of the cosmos. It is just that at one point the cosmos was the size of a marble. -- Colin Angus Mackay
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Christian Graus wrote:
Assuming you do not, assuming the method just does the remove and returns true if the item is removed, or did not exist, then when will it return false, in that instance ?
Assuming you don't want to do additional processing then my vote for 1.0 applies and that's that. But really... if your not going to do anything else you don't need a result do you? Make it void unless you intend to throw an error in the case it finds nothing. If you don't wish to do additional processing you don't need any return just void it.
Yeah, ultimately, I don't think a return value is needed or justified, if all you're doing is removing an item. But, the question didn't ask that :-)
Christian Graus - Microsoft MVP - C++ Metal Musings - Rex and my new metal blog "I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )
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Here's a philosophical question: If you have a function that is meant to delete an item from a collection and the item you wish to delete doesn't exist, do you: 1. Return TRUE since the final outcome (not having that item) has been fulfilled, or 5. Return FALSE because since the function couldn't find the item, it couldn't actually delete it. Vote now.
cheers, Chris Maunder
CodeProject.com : C++ MVP
The 9 things Microsoft should be announcing at MIX07 (but won't)
Add a boolean field and property so the user of the collection can specify what he wants.