Straw Poll: Return True or False?
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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)
The typical approach in the .NET Framework seems to be returning false because the item wasn't in the collection and wasn't actually deleted. It's pretty intuitive too, I suppose. If you make the call expecting the item to be deleted, and the return value says it wasn't, you might at least want to log it.
Cheers, Patrick
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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)
I voted a 1 but I would have to say that it depends on if you need to do additional processing after the delete. I mean if it doesn't find anything perhaps that means you want to insert a value somewhere else then you'd want to have a false result.
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
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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? Return a reference to the removed item or null. Throw an exception if necessary.
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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)
If there's any other reason for delete to fail, you need an enum. Otherwise, the only possible answer is false. Otherwise, when would you return false ? You'd return true for found it and deleted it, or true for didn't find it, the return value would be useless.
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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I voted a 1 but I would have to say that it depends on if you need to do additional processing after the delete. I mean if it doesn't find anything perhaps that means you want to insert a value somewhere else then you'd want to have a false result.
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
If you return true for 'I found it and deleted it', and true for 'I couldn't find it, so I didn't have to delete it', what would return false ?
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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If you return true for 'I found it and deleted it', and true for 'I couldn't find it, so I didn't have to delete it', what would return false ?
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 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
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If there's any other reason for delete to fail, you need an enum. Otherwise, the only possible answer is false. Otherwise, when would you return false ? You'd return true for found it and deleted it, or true for didn't find it, the return value would be useless.
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:
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)
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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)
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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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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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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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.
image processing toolkits | batch image processing | blogging
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)
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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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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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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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