Hi, I cant quite figure out the point in dynamically creating variables using the new keyword. I mean what difference doesi t make if i create an int like int number = 0; or new int number = 0;

One is allocated within the .exe file (space is reserved), while when using new, it allocates the memory when the function scope is reached. I beleive that''s the only major difference.

new/delete are more used for dynamic sized arrays and stuff.

Well if you do:

int var;

your application is going to take up 4 bytes for the entire time it runs and that 4 bytes is not reusable.

if you do:

int *var = new int;

then your application will take up 4 bytes until you delete it. This way it''s reusable.

Dynamic memory allocation is useful when you don''t know the sizes of things like images. Is it 640x480 or 1280x1024 in size? If you don''t know then you need to make a huge array and waste space.

Dynamic memory is a way of using the memory available more effectively than just using plain old static memory

new is useful for situations in which it is not known how much memory will be needed before the program actually runs. A good example of this is strings. Suppose all of your strings are statically allocated character arrays. There will be times when you will run out of space when trying to write to a string. And there will also be times when you are only using a small fraction of the allocated space, and are therefore wasting memory.

Dynamic memory is useful in such situations because the amount of allocated memory can be adjusted depending on how much is needed. There are many other uses, especially in data structures (linked lists, binary trees, hash tables, etc.)

Of course, though this is one of the most useful language features, it is also the most dangerous. A large proportion of programming errors are caused by the misuse of dynamic memory.

-D

It''s needed for things like dynamic arrays, linked lists or trees, and using polymorphism.

As you continue to learn C++ you will see the importance of dynamically allocating memory.

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