realloc in C++

[divya_rathore_]

Old question in a new bottle:

What if i delete a 1D array and again use new to allocate a bigger (or
smaller) size?
is this ok? Feel free to shoot me!

int *array;
int size = 100;

//allocate memory for 'size' no of integers.
array = new int[size];
//fill up the 'array'.
for (int i=0; i<100; i++) array = i;

//delete data pointed to by 'array'
delete[] array;

//again allocate but a bigger size!!
//is this ok??
array = new int[200];
//fill up the 'array'.
for (int i=0; i<200; i++) array = i;

//delete data pointed to by newly allocated 'array'
delete[] array;


Compiler specifics: Microsoft visual studio ver 6.0 and higher.
What I know: it can be done using STL, I KNOW. But how right/wrong is
the above approach?

 

[=?ISO-8859-15?Q?Juli=E1n?= Albo]

What if i delete a 1D array and again use new to allocate a bigger (or

You never 'allocate again', you just allocate. The fact that you assign the
result of the allocation to the same pointer than a previous allocation is
completely irrelevant.

 

[divya_rathore_]

result of the allocation to the same pointer than a previous allocation is
completely irrelevant.

pardon me.. but that means..?
Would it work or not?

thanks in advance!

 

[divya_rathore_]

Would it work or not?

and moreover, is it an acceptable practice?

thanks again in advance..
cheers!

 

[Jim Langston]

and moreover, is it an acceptable practice?

thanks again in advance..
cheers!

Yes it would work. Yes, I've seen it done. Where you would do this depends
on your program.

I can see std::vector doing this exact thing (not sure if it does, but I
could see it implemented this way).

 

[=?ISO-8859-15?Q?Juli=E1n?= Albo]

and moreover, is it an acceptable practice?

It works and is acceptable.

 

[Daniel T.]

Old question in a new bottle:

What if i delete a 1D array and again use new to allocate a bigger (or
smaller) size?
is this ok?

Yes, it is OK, though I suggest you use std::vector instead.

int *array;
int size = 100;

I believe the above needs to be a const int.

//allocate memory for 'size' no of integers.
array = new int[size];
//fill up the 'array'.
for (int i=0; i<100; i++) array = i;

//delete data pointed to by 'array'
delete[] array;

//again allocate but a bigger size!!
//is this ok??
array = new int[200];
//fill up the 'array'.
for (int i=0; i<200; i++) array = i;

//delete data pointed to by newly allocated 'array'
delete[] array;

 

[divya_rathore_]

It works and is acceptable.

Thanks a lot, Jim and Julián! I will do some tests and revert back
with my observations.
thanks again

- divya rathore
(remove all underscores for email ID)

 

[Sylvester Hesp]

Yes, it is OK, though I suggest you use std::vector instead.


I believe the above needs to be a const int.

Why? For the 'array = new int[size];' statement? That's not true, of course
new array expressions can take nonconst integrals, otherwise they would be
pretty useless

- Sylvester

 

[Daniel T.]

Yes, it is OK, though I suggest you use std::vector instead.


I believe the above needs to be a const int.

Why? For the 'array = new int[size];' statement? That's not true, of course
new array expressions can take nonconst integrals, otherwise they would be
pretty useless

True, my mistake. I was thinking about auto arrays.