delete or delete[]

Hamed Musavi

I've seen some codes using delete[] blah; and someone else delete blah;. I didn't read in any book how to use them and what's difference. It's a couple of years that I'm programming and using just delete. Does any one know what is the difference and when we need to use those brackets?

// "Life is very short and is very fragile also." Yanni
while (I'm_alive)
{
cout<<"I love programming.";
}

jhwurmbach

Hamed Mosavi wrote:

delete[] blah; delete blah;. what's difference

Simple: If the memory was newed with [], use delete[], otherwise normal delete. delete[] calls the destructors of the elements of the array before freeig the memory, whereas delete does not. You might get away with using the wrong one, until you are really under pressure. Then the whole shit will explode in your face.

Though I speak with the tongues of men and of angels, and have not money, I am become as a sounding brass, or a tinkling cymbal.
George Orwell, "Keep the Aspidistra Flying", Opening words

led mike

Hamed Mosavi wrote:

I didn't read in any book how to use them and what's difference.

Why not?[^]

Hamed Musavi

What a big memory leak in some of my applications.:sigh: Thank you.:)

// "Life is very short and is very fragile also." Yanni
while (I'm_alive)
{
cout<<"I love programming.";
}

Hamed Musavi

Thanks.

// "Life is very short and is very fragile also." Yanni
while (I'm_alive)
{
cout<<"I love programming.";
}

jhwurmbach

Wow - four letter words get automagically beeped here. I did write a 'i' instead of a '*" in the post above. -- modified at 11:46 Wednesday 15th August, 2007 Being too soapboxy

Though I speak with the tongues of men and of angels, and have not money, I am become as a sounding brass, or a tinkling cymbal.
George Orwell, "Keep the Aspidistra Flying", Opening words

Nemanja Trifunovic

Hamed Mosavi wrote:

What a big memory leak in some of my applications.

Not necessarily[^] if you were using VC++, at least according to Stan Lippman. But in general, this leads to undefined behavior and should be avoided.

Programming Blog utf8-cpp

Hamed Musavi

I was wondering why I didn't notice this type of memory leak reports already. I'm mostly very careful about it. I used vld dll for a while. So it is possible that this does not result in a memory leak in VC++, but worse than that, it might lead to an unknown behavior. Why VC++ compiler doesn't generate a warning? or perhaps it does in level4?(I often use the default level3)

// "Life is very short and is very fragile also." Yanni
while (I'm_alive)
{
cout<<"I love programming.";
}

Nemanja Trifunovic

Hamed Mosavi wrote:

but worse than that, it might lead to an unknown behavior

No, my understanding is that with VC++ it works fine either way (haven't tried it though :) ). However, the C++ Standard says that such a case leads to undefined behavior which means that with other compilers (or a new version of VC++) you may see just about anything at all: leaks, crashes, destructors not being called - you name it.

Programming Blog utf8-cpp

Hamed Musavi

Thanks.

// "Life is very short and is very fragile also." Yanni
while (I'm_alive)
{
cout<<"I love programming.";
}

karle

you must call delete [] if you have an array of objects. if you leave out the [] the destructor only is called for the first object of the list. So, to be sure not to get resource/memory leak you have to use [] for arrays.