Question about deleting objects in C#

[n00b]

Hello everyone, I just had a question about deleting objects in C#.

For example if I have a string array and I wanted to make it grow by one size adding the string "dd" to it.

string[] array = new string[] {"aa", "bb", "cc"};
string[] temp = array;

array = new string[temp.length+1];
array[3] = "dd";

So before the line "array = new string[temp.length+1];" do I have to delete the old array data first to prevent memory leak? Thanks!

[r035198x]

Hello everyone, I just had a question about deleting objects in C#.

For example if I have a string array and I wanted to make it grow by one size adding the string "dd" to it.

string[] array = new string[] {"aa", "bb", "cc"};
string[] temp = array;

array = new string[temp.length+1];
array[3] = "dd";

So before the line "array = new string[temp.length+1];" do I have to delete the old array data first to prevent memory leak? Thanks!

Throw everything away and use an ArrayList instead.

[mikeyeli]

Hello everyone, I just had a question about deleting objects in C#.

For example if I have a string array and I wanted to make it grow by one size adding the string "dd" to it.

string[] array = new string[] {"aa", "bb", "cc"};
string[] temp = array;

array = new string[temp.length+1];
array[3] = "dd";

So before the line "array = new string[temp.length+1];" do I have to delete the old array data first to prevent memory leak? Thanks!

you could get rid of the old array, but there really is no need since there is a garbage collector, no need to worry for such things....you might want to leave temp pointing to null after copying it, so the garbage collector takes care of it faster.

[Plater]

Doing this part:
array = new string[temp.length+1];
array[3] = "dd";

will wipe out what you had with [0] [1] and [2] (the "aa" "bb" and "cc")


If you want to add/remove items from an array dynamically, look at the Systems.Collections namespace and pick something out of there. ArrayList, LinkedList any number of them

[n00b]

So with the implementation that I have,
ie" array = new string[temp.length+1] does that actually make a new string array in dynamic memory?

Doing this part:
array = new string[temp.length+1];
array[3] = "dd";

will wipe out what you had with [0] [1] and [2] (the "aa" "bb" and "cc")


If you want to add/remove items from an array dynamically, look at the Systems.Collections namespace and pick something out of there. ArrayList, LinkedList any number of them

Err sorry I forgot a for loop in there that copies the 3 elements from temp into array.
Oh man I totally forgot that C# has a built in Linked List library, lol I was thinking of using one but didn't wanna create it by scratch. Thanks for the input everyone!

[r035198x]

So with the implementation that I have,
ie" array = new string[temp.length+1] does that actually make a new string array in dynamic memory?



Err sorry I forgot a for loop in there that copies the 3 elements from temp into array.
Oh man I totally forgot that C# has a built in Linked List library, lol I was thinking of using one but didn't wanna create it by scratch. Thanks for the input everyone!

Yep, that is generally the meaning of "new".
B.T.W You want to use ArrayList for this not LinkedList

[n00b]

Yep, that is generally the meaning of "new".
B.T.W You want to use ArrayList for this not LinkedList

Ah okay that's what I thought, just wanted to double check.

How do you delete the old object? I know in C++ there's a delete command you can type that does that, but doesn't seem to be the case for C#. Or is it just setting it to null?

[Plater]

Setting an object to null tells the garbage collector that you're done with it and to free up the memory you are using.
(Provided there are not certain circumstances, such as an open file handle or open stream or socket)

Some object also contain a .Dispose() which does a good job at clearing up the memory too.
You can also force a collection with GC.Collect().

[n00b]

Setting an object to null tells the garbage collector that you're done with it and to free up the memory you are using.
(Provided there are not certain circumstances, such as an open file handle or open stream or socket)

Some object also contain a .Dispose() which does a good job at clearing up the memory too.
You can also force a collection with GC.Collect().

Ah i see that sounds good. Thanks everyone for their help!

[r035198x]

Just thought I'd add that calling GC.Collect() simply marks legible objects as free. The actual memory release is done if the OS needs the memory for other programs. In essence, one doesn't know the exact moment that memory is released for a particular object.