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#ActualMarkS

Posted 15 October 2012 - 01:40 PM

quite good suggestion, BUT: in the cleanup function check for NULL and if not, then delete and assign to NULL. Posted Image. I know that delete checks if the pointer is NULL, but for teaching purposes it is good to suggest that. Also, setting it to NULL after deleting is not mandatory, but is, again, good practice and, perhaps, would keep the user to double delete the same pointer and/or access it after deletion.


After reading what Servant of the Lord wrote on this, I really can no longer say it is good practice. Let's say that I do call delete on a pointer twice. If I set it to NULL, nothing happens and the error is never found and corrected. However, if I don't, the program crashes and the error gets fixed. It would seem to be better practice to not give yourself the ability to do things incorrectly in the first place.

Sorry to double post, but, for learning purposes, here's another suggestion: If you want to track "troublesome bugs" with memory allocation (i.e. using pointers after you delete them - happens more often than you think), you set them to an invalid, but easily recognizable value, kinda like 0xfefefefe. Then, when the program blows to bits, you look at the pointer in the debugger, and if it matches (or it is close) the 0xfefefefe, you know you have this problem. enjoy


I like this idea.

#3MarkS

Posted 15 October 2012 - 01:38 PM

quite good suggestion, BUT: in the cleanup function check for NULL and if not, then delete and assign to NULL. Posted Image. I know that delete checks if the pointer is NULL, but for teaching purposes it is good to suggest that. Also, setting it to NULL after deleting is not mandatory, but is, again, good practice and, perhaps, would keep the user to double delete the same pointer and/or access it after deletion.


After reading what Servant of the Lord wrote on this, I really can no longer say it is good practice. Let's say that I do call delete on a pointer twice. If I set it to NULL, nothing happens and the error is never found and corrected. However, if I don't, the program crashes and the error gets fixed. It would seem to be better practice to not give yourself the ability to do things incorrectly in the first place.

#2MarkS

Posted 15 October 2012 - 01:38 PM

quite good suggestion, BUT: in the cleanup function check for NULL and if not, then delete and assign to NULL. Posted Image. I know that delete checks if the pointer is NULL, but for teaching purposes it is good to suggest that. Also, setting it to NULL after deleting is not mandatory, but is, again, good practice and, perhaps, would keep the user to double delete the same pointer and/or access it after deletion.


After reading what Servant of the Lord wrote on this, I really can no longer say it is good practice. Let's say that I do call delete on a pointer twice. If I set it to NULL, nothing happens and the error is never found and corrected. However, if I don't, the program crashes and the error gets fixed. it would seem to be better practice to not give yourself the ability to do things incorrectly in the first place.

#1MarkS

Posted 15 October 2012 - 01:37 PM

quite good suggestion, BUT: in the cleanup function check for NULL and if not, then delete and assign to NULL. Posted Image. I know that delete checks if the pointer is NULL, but for teaching purposes it is good to suggest that. Also, setting it to NULL after deleting is not mandatory, but is, again, good practice and, perhaps, would keep the user to double delete the same pointer and/or access it after deletion.


After reading what Servant of the Lord wrote on this, I really can no longer say it is good practice. Let's say that I do call delete on a pointer twice. If I set it to NULL, nothing happens and the error is never found and corrected. However, if I don't the program crashes and the error gets fixed. it would seem to be better practice to not give yourself the ability to do things incorrectly in the first place.

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