Does the detele operator in C++ de-allocate a single address or a block?

Asked Dec 26 '16 at 03:40

Active Dec 26 '16 at 04:38

Viewed 36 times

Suppose a block is allocated on the heap to hold an array of integers. While de-allocating, should I use the delete operator once on the entire block or once on each byte? As an example, consider

int *ptr=new int[n]; //n is a natural number 
.....
delete[] ptr;   //Is this the right approach? or 
for(unsigned int i=0;i<n;i++) delete[] (ptr+i); //this one?

To me, the second approach seems more natural. Otherwise, when passed an address, how does the delete operator know how far along the line should it de-allocate? Or does it just continue to de-allocate as far as it can see an allocated byte?

edited Dec 26 '16 at 04:38

Shreyash S Sarnayak

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asked Dec 26 '16 at 03:40

Della

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`delete[] ptr;` is what you need. – drescherjm Dec 26 '16 at 03:42
`for(unsigned int i=0;i – drescherjm Dec 26 '16 at 03:42
***how does the delete operator know how far along the line should it de-allocate?*** typically new will store the size of the allocated block somewhere. – drescherjm Dec 26 '16 at 03:43
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http://stackoverflow.com/questions/197675/how-does-delete-know-the-size-of-the-operand-array – A.S.H Dec 26 '16 at 03:45
Maybe it stores the size of the block allocated just before the allocated block. This way whenever you delete it, it goes one byte back and gets the size. – Shreyash S Sarnayak Dec 26 '16 at 03:48

Does the detele operator in C++ de-allocate a single address or a block?

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