Hi All,

Could any one give an example in which case we can use static object
(CAbc abc; )
and in which case we use dynamic object(CAbc *abc = new CAbc(); )...?

Best Regards,
Janakiraman

Dynamic - anywhere you want.
Static - in static functions.

Static objects are deleted when they go out of scope, but you must remember to delete a dynamic object. Often this is not done, and memory leaks ensue.

A developement technique that I use to help prevent this is to run the software in debug mode in Visual C++ Dev studio, with no break points. When it completes, you can see if it has memory leaks. Do this one quick simple check everytime you add the posiblity of using an object and you should end up with no memory leaks.

When does static object exits its scope?

I could be wrong, but I believe a object declared as (CAbc abc would go out of scope in exactly the same way a variable would. So if it was declared in the function, then it would be deleted when the function exits. The compiler would have allocated some space for it at compile time. The information within that object being unavailable after the function has exited.
Try looking at this:

Well naturally if you declare on static object in the function then it won't be seen in other functions, these kind of objects are usually used for counting in recursion, but it is not deleted in the end of the function - this is its purpose to save info after the end of the function.

I am slightly confused.

Are you talking only about memory allocation?
Or about static keyword, etc?

For me, I was only talking about a class object declared as CAbc Abc; not a static variable which would exit after the function has exited, but still only be available within the scope of the function... since it was declared there.

A quick point about reply from Aie0.
A good point you have made. However, since the variable is out of scope when the function exits, doesnt the variable space become usable again for the program. In this sense, isnt the object deleted. The class objects were not declared using the keyword "static" so I think they would be deleted. If the keyword "static" had been used, then the values in the object would remain and could be used if the function was ever re-entered. In this case I would expect to have had a memory leak when the program ended. Do you think this would be the case?

Also, try as I did, I could not get a memory leak with the tiny bit of knocked up code I put forward. I wonder if this is something to do with it being run in a consol window, rather than a windows window.

I supose in conclusion, I must confess to not knowing how to describe a object which is made by (CAbc Abc) and (CAbc *p = new CAbc()). Most of the time i use objects declared like (CAbc Abc) is within another class header file, so in that case they are static for the duration that that class object eixts. Perhapes someone can enlighten me as to the correct terms to use.

If you declare a class like this
Then it is auto-destructed in the end of the braces where it was declared and is called local variable.
If you declare a class like this

Then it is not destructed in the end of the function and can be reused in the next call of the function and it is called static variable. If the class holds any pointers they must be destructed implicitly when it is known for sure the class won't be used again.
If you declare a class like this

Then it also not destructed but if you don't transfer the pointer to somewhere at the end of the function then it will be lost and memory leak is what you will get, called dynamically created class.
If you define class like this
Then it can be used without declaring an in stance of it, meaning that you can call its methods without declaring for the class. Often used for math classes.