Teach Yourself Borland C++ in 14 Days - portal

Up to Your Neck in C++
If you are attempting to allocate very large chunks of memory (several
megabytes in size) or are trying to allocate memory at critical points in
your program, you should check the pointer for validity before continuing.
For routine memory-allocation chores, you can probably get
by without checking to ensure that the new operator succeeded.
delete
All memory allocated must be deallocated (released or freed) after you are done with the
memory. With local objects, this happens for you automatically, and you don’t have to worry
about it. The memory manager allocates the memory your object needs from the stack and
then frees that memory when the object goes out of scope (usually when a function returns
or when the code block in which the object was declared ends). When using dynamic memory
allocation, the programmer must take the responsibility of freeing any memory allocated with
the new operator.
NEW TERM
WARNING
Freeing memory allocated with new is accomplished with the delete operator.
All calls to new need to have a matching delete. If you do not free all
memory allocated with the new operator, your program will leak
memory. You need to be diligent in matching new/delete pairs.
Using the delete operator is frightfully easy:
SomeObject* myObject = new SomeObject;
// do a bunch of stuff with myObject
delete myObject; // so long!
That’s all there is to it! There isn’t a lot to the delete operator, but there are a couple of things
about pointers and delete that you should be aware of. The first is that you must not delete
a pointer that has already been deleted, or you will get access violations and all sorts of other
fun stuff. Second, it is okay to delete a pointer that has been set to 0. So what does that mean
in the real world? Let me explain.
Sometimes you declare a pointer just in case it might be used, but you don’t know for sure
whether it will be used in a given instance of your program. For example, let’s say you have
an object that is created if the user chooses a certain menu item. If the user never chooses that
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